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The NC-4 transatlantic flight seaplane aloft, as seen from one of her companion flying boats 








The Vickers " Vimy " bomber leaving St. John's for the non-stop transatlantic flight 



.TEXTBOOK 

OF 

APPLIED 
AERONAUTIC ENGINEERING 



HY 




HENRY WOODHOUSE 



u IHOR OF "TEXTBOOK or KAVAI AEBONAI n. ." "IIXTBOOK or MILITARY 

AERONAUTICS," "AIRO BIXE BOOK." 
MEMBER or TIM: BOARD of UOVKRNORR or AKRO nr or AMERICA. vici-l-Rrsn.. v t 

AKRIAl I I V..' r. Or AMERICA, MEMBER OF NATIONAL AERIAL COAST FATROL COM- 

MI-.IMS. III. Mil VM..IIVI..MVX ol COMMITTEE OK AERONAl'TK NATIONAL 

iv-HTITr OF Fill. II- Y. MEMBER OF THE gOCIKTY Ot AVTOMOTITE 

ri -|UM VM> INDI-ITBIAI. DEI.EOATE 
PAN-AMERICAN FEDERATION. ETC., ETC., ETC. 




NEW YORK 
THE CENTURY CO. 

1920 



3 



Copyright, 1920, by 
THE CENTUBY Co. 



Published, January, 1920 



Textbook of Applied Aeronautic Engineering 



INTRODUCTION 



Thi- ni-nunm-nt.-il work on aeronautic -n-in, -. mi- i- 
,-inl importance .-ind value .-it this time In cause it 
tells in a simple laminate, anil without difficult formulas. 
Imu l.-iri." icroplancs ..in ! Imilt for arrial transporta- 
.TII!. by i:ivini: tin drawings, ili aurains and photo- 
graph- iif existing ami (iroposrcl types of aeroplane- 
.iii,l i . iltli nt engineering data, will ,-issist engineers in 
hiiildint: aeroplane- large and small, for .-irri.-il transporta- 

ul other purposes. 

While travelliii!: tlirouiili South and Central Am- ri.- i 

\ I was n-mimli-d daily that South and Central 

rii-a in waiting fr aerial transportation. 

In tin i eoiintrii-s we have many ditlieult prolili-nis of 

traiisportati..ii whieh eati lie easily solved liy aircraft. 

L'pon the solution of this, prohlems depends the cco- 

noniie wcifa'rc and eiiiiim-rei.il developmi-nt of these roun- 

trie-. lii re mountains, forests and waterways make the 

of building railroads prohihitiv- 

The stupendous flights of the X. ('. I. the Vickers 
"Vimy and other large aeroplanes have aroused hopes 
that i. rial transportation lines will be established in the 

future. 

In everv o n. of tin Latin Amerieaii countries there arc 
people with imagination and capital who would like to 
tak. steps to establish air lines, but they do not quite 
know how to go about it. Soon, we hope, enterprising 
experts in the I 'nit-d States will come to our assistance 
and establish these lines. 

While tin- I'an American aeronautic movement is youth- 
ful, having IM-I-II conceived by Mr. Henry WoodhoUM in 
I'll I. and -volvcd l>y him and the other energetic and 
in- men. who are responsible for so many im- 
portant aeronautic movements Messrs. Alan R. Hawley. 
H. ar Vdmiral Hob, rt K. Peary, John Barrett, and Henry 
A. \\ i- Wind it is advancing in gigantic strides. 

ins, of the broad expanse of territory, the lack 

of roads into all sections of the country, the excellent 

ways, all kinds of aircraft will be of great value to 

tin I'nitcd States and Canada, as well as to South and 

r.d America. 

I u. years ago I went with Mr. Woodhouse to visit 

tin ( urtiss Aeroplane factory at Buffalo. The pur|M>sc 

of our visit was to prove to ourselves that an aeroplane 

.etually being built that could lift a ton. Reports 

had bei n circulated that such an aeroplane was being 



designed, but the thing was not considered possible or 
practical. Mr. Woodhouse and mvs.l! had IM-I-II study- 
ing the need of aerial transportation in South ami < n 
tral Am. ne.i and w. rcali/.rd that, if it was true that 
such an aeroplane was Ix-ing built, there were prospects for 
the establishing of aerial transportation lines in South 
and Central America within a few years, which would 
solve the difficult problems of transportation. We went 
to HuH'alo with keen , \peetation. but did not expect to 
actually see a large aeroplane under construction, be- 
cause at the time even the highest engineers did not 
admit the possibility of building large aeroplanes that 
would fly successfully. They generally held that a, n. 
planes with two motors were impractical, because in the 
event of one motor stopping, the aeroplane, according 
to their computations, would spin around and it would 
be impossible for the pilot to control it. They also held 
that propellers would not stand the vibrations of high 
horse power engines. 

To our great satisfaction and wonderment we found 
in the Curtiss factory a huge seaplane almost completed 
which, we know now. was a prototype of the N. C I. 
which Hew across the Atlantic. 

I clearly recall how very few people believed an 
when we reported to them what we had seen. It seemed 
impossible ! 

In this valuable Textbook. Mr. \Voodhousc points out 
the possibility of building aeroplanes to lift twenty tons 
of useful load, and he explain* hou- H can be done! 
It is not prophecy on his part; it is knowledge of the 
broadest aspects of aeronautic engineering and of the 
aeronautic art as a whole, with the development of which 
he has Ix-cn closely identified for the past ten years. 

Furthermore. Mr. Womlhouse urges original experi- 
ments in the distribution of the 10,000 square feet of 
wing space which is required to lift twenty tons of us, 

ful load. 

He presents the problems to be solved in clear, simple 
language and clearly defines the factors which will make 
for success in developing large machines for aerial trans- 
portation. Then-fore, this Textbook will be of great 
assistance to aeronautic engineers and to every IMTSOII 
who is interested in the development of aerial trans- 
portation and the use of aeroplanes for general pur P 

ALBERTO SANTOS-DI-MONT, 

Honorary Prrtiilrnl l'a-.-lmrrira 

.Irronaulir pntrratiii*. 



r, .; 



CONTENTS 



PAGE 

CHAPTER I STATI-S OF APPLIED AERONAITI. Bva 

NKKUINIi 3 

\\.ir Developed Speed Kcgardlcss of Klying Kfficicllt-y 3 
,t Bomliini: and Antiaircraft llrnii^ht . \lMint Vnl- 
lialilr DcM-lop Mil-lit-, ill AiTi>|.|.-inr Construction . 5 

K.ngiiiecrintr \il\antiijrcs in I Urge M i. hines ... o 

Phwoixl Coiistrm -lion Our t Most Important l>,\.| 
incuts 

T\p.sot II. .*icr Th.in \ir Aircraft 7 

Status .if Present l>.-i> Aeroplanes . 

Detailed Views of NC-l Transatlantic T\ pc Seaplane 12 

Cellini: tin- Sniiif KngiMccring liesiilts liy Diffi-rrnt 

Distriliiiti.uis of \Vin;r \re.i .... 14 

Mow Can \Vr DistriUitc tli.- KMKI Square Feet of 
Wing Surface ltri|iiiri-.l to Lift -' Tons of L'se- 

ful l.oadr 1 

\rca Distrih-ition. Win^s with \-pcct Uatin of 6 to 1 17 

Kclation of Cap to Chord 17 

Tandem Planes lti-pr.--.-nt tin- Solution 

I'rolilenis of Trussing HIM! Bracing 

B.xlv C. instruct ion 19 



II Mi I.TI 



AEROPLANES 



23 



The .i-Motornl C.-riiian Biplane . 

Tlir l-Motornl Voisin Triplane ....... -'"' 

Hi,- t Moton-d llaiidlcy-Pagc Biplane ..... -'> 

III.- l-Mot.ir<-il Sikorsky Biplane ....... -' 

Hi, I M,.lor,-d Zeppelin Biplane . . 

x -Curtiss No I TnuiMitlantic- SfiijtUne 33 

The Capraol Bombing TrtpUne Type CA-4 . ... 37 

Curtiss II li- A l-'lyinu Boat ........ 41 

I , I \ ivj I l\ini: Uoit . . . 

il.in.ll.-> Page Type O-MM Bomber ..... +7 

Tlir Martin Cruisinjr Bomljer ........ *0 

Cl.-iiii 1.. Martin Bomlx-r ......... ' 

Siiiulstitlt-lliinnrvi); Si-a]>lnnr ...... 

Bur^'--' Twin-.Motcin-il llydroai-roplani- ..... 59 

Thr TransatlantU- 'I'vpr VirkiTs - \'iiny " .... 60 

Uro Twin l-'.njrini-d Bonilx-r . . . 
Ijiwson Aerial Transport . 

The Krii-ilri.-li-.hafm Twin-Motoml Biplane ... 67 
The Cotlia Twin-Motor.-d Biplane - Type (5O. G5 . 

The C.-rman A. K. C . ({.milling Biplane .... 79 

Cnrtixs M.xlrl 1H-B Biplane ....... "0 

The Cnrti-s "Oriole" Biplane ....... 81 

C'n \PTER III SiNoi.K MOTORED AEROPLANES . . 82 



The Ai-riniiiiriiK- Tniininp Tractor ...... 

The Hellnnea Biplane .......... * 

Cnrtiss M.Hlrl .IN-tl) Tra.-tor ........ 87 

The IV Havillan.l t Trai-tor Biplane ...... * 

The I). II. '. I'ursiiit Biplanr ........ 93 

The I).- llavillanil No. 5 ......... 94 

I'hr T-l MesM-np-r ........... 96 

The Berekman-. Speeil Si-out ........ 

The Christinas Stnitlrss Biplane ....... 101 

The I,nws,m M. T. -' Traetor Biplane . . . 
Oallnudrt K.-l. .' Mononl.inr ... 

The C.allnnilet K.-l. .' " Chiiiiimy KlynlK.nt " Monoplane 1M 
The I.e Pere Kijihter .......... 1" 

Onlnanre Knaineerlne Srout SO Ix-Rhftne . 

The (). I. . C TM..-S B ami C Single Sealer . . . . 1O9 

The Martin K-III Single Sealer ...... 

The Parltanl Aeroplane ..... 11* 



FAOE 

The Standard K-l Single Seater 117 

The VK-7 TraininK Biplam- ll 

The Three-Motored White Monoplane 119 

The Standard Mo.1,-1 I. I Mail Aeroplane . . . . 1-'" 

Thomas-Morse, T\| " l< s mv .|,- ^-ater Sront . . 1.'-' 

Thomas-Morse, T\ p. - II Sin^le-seiiter Scout . . 1-'-' 

Thomas-Morse, Type -S-ti Tandem Two-seater . . I-"-' 

Thomas-Morse, T>pe S 7 Side. I.) -Side To-seater . I .'. 

The Thomas-Morse Type M-B-H, :X) h.p. Ilispano 

Kncine KiRhter ." l-'l 

The Kren.h A. . Biplane IM 

The Bn-truet Biplane 1JH 

The Sopwith Maehine 130 

The Short .Miii-hine ISO 

The Martinsyde Type l:JI 

Crahame-White \.-ro Limousine . 1:1-' 

The C.TIM:, ii Gothas. th. Aviatiks and the Ago Bi- 
planes l: 

The Nieiiport P. Planes 135 

The S|>a.l Seoul. Type S VII I.! 1 ' 

Bristol Si-out so I.e l< hone 11:1 

I S. B.-l British Kighter 1** 

300 Hispiino-Siiizu {'. S. Army Tests 144 

Martinsydr Seoul IWKI I lispaiio-Suizii 147 

The Knglish S. K. :> Single-Seiiter Kighter .... 151 

S. K. j IKO llis]).ino-Suixa 154 

The British Sopwith Planes . . 15fi 

The Sopwith "Camel" 156 

British Avro Aeroplanes 157 

The S. V. A. Kiphtinp Seoul 159 

The I'oinilio Heeonimissanee T\ pe Traetor .... 161 

The A. K. C'i. Cerman Armored Biplane .... 163 

The German Api Kighling Biplane 165 

The Allmtros Type "I V " 1-Vt" I 70 

The Kokker SinVlf Seater Biplane T> pe O-7 . . 186 

Tlie Tarranl "TalMir" Triplane 191 

The MallH-rstadl l-'ighter '"-' 

The Cerman llansH-Brandenhiirg Traetor .... 195 

Details of Ihe Austrian Hansa-Brandeiihiirj: Traetor l'i; 

The Wittemann-I.rwis Commereial Biplane .... 198 

The Holand Chaser I). II -'IX) 

The I.. V. C. Biplane Type C. V 

The Ae.-Mot.ired Single Seater Aee Biplane . . . iK)4 

The Hannoveraner Biplane 207 

IlallM-rstadt-Kil) Mem-des JOB 

The PfaU Biplane I). Ill -M" 

Pfalr. Seoul S.* I I7-1WI Mer.-edes JU 

Trails on Avialik No. G.IMJ. I . 214 
Dimensions and Kquipmrnt of Ihe 1918-1919 Types of 

Cerman Aeroplanes -'I* 

The C. IV Kiimpler Biplane 216 

The Curtiss Model IH-T Triplane .... 

The Sopwith Triplane . 

Perspective Sketches of the Cerman Kokker Triplane J.'t 

The Kokker Triplane 

The Aeromarine Training Seaplane 

The Aeromarine " T-.VI " Three Seater Flying Boat . 

Boeing Seaplane Type C-I-K ** 

The Burgess Speed Scout Seaplane 

The Curtiss II- \ Hydro 23M 

Curtiss M.Kl.-l IIS- .'-I. Klying Boat 235 

Curtiss M.nlel MK Klying Boal . . 

The Gallaudet D- l.iirht Bomlx-r S-apliine 

Thomas-Morse T\ pe -S-.'. Single-seater Seaplane . . 241 

V, v i M .' Bahy Seaplane 

The'K. B. A. Klying Boat .... 243 



CONTEXTS 



Au*triiin Apo Flyinsr Boat 2*8 

The Lohner Flying Boat 2*9 

CHAPTER IV AEROPLANE AND SEAPLANE ENGI- 
NEERING 251 

CHAPTER V NAVY DEPARTMENT AEROPLANE SPE- 
CIFICATIONS 263 

CHAPTER VI METHOD OF SELECTION OF AN AERO- 
PLANE WING AS TO AREA AND SECTION . . . 271 

CHAPTER VII NOMOGHAPHIC CHARTS FOR THE 

AERIAL PROPELLER 276 

CHAPTER VIII METHODS USED IN FINDING FUSEL- 
AGE STRESSES 280 



PAGE 

CHAPTER IX THEORY OF FLIGHT 28 1 

CHAPTER X SHIPPING, UNLOADING AND ASSEMBLING 29-1 

CHAPTER XI RIGGING 296 

CHAPTER XII ALIGNMENT 303 

CHAPTER XIII CARE AND INSPECTION .... 308 
CHAPTER XIV MINOR REPAIRS 310 

CHAPTER XV VALUE OF PLYWOOD IN AEROPLANE 

FUSELAGE CONSTRUCTION 312 

Properties of Various Woods 315 

CHAPTER XVI NOMENCLATURE FOR AERONAUTICS 316 
The Metric System .324 



TEXTBOOK 

OF 

APPLIED 
AERONAUTIC ENGINEERING 




Hear view of the 1903 Wright 1 lyrr The first aeroplane to fly. 



CHAPTER I 
STATUS OF APPLIED AERONAUTIC ENGINEERING 



Aeronautic Kngineering as an applied art is 
only ;i few years old. 

From December 17. 1903. when the Wrights 
made their first flight, to 1916, tin- world's aero- 
nautic engineers were so few that they could be 
counted mi one's finger tips. 

In 1 !!_>. there were no schools of aeronautic 
cn-rim-cring and Mr. Henry A. Wise Wood, the 
editor ,,f "Flying Maga/ine," and the writer 
urged tlie leading Universities to establish a 
course ill aeronautic engineering. Only one 
University responded. The others stated that 
the need for such a course was not sufficiently 
evident to justify the step. 

In 1917-1918 courses in aeronautic engineer- 
ing were established at a mimlrcr of Universities, 
but the purpose was mainly to give cadets an 
elementary course on the theory of flight; to 
teach them the most elementary principles in 
the slim-test time possible. 

The text of the most complete course of its 
kind is reproduced in the Index, entitled 
"Theory of Flight." 

The greatest work in aeronautic engineering 
in the United States was done at the U. S. 



Army Aeroplane Engineering Department at 
Dayton in 1918-1919 and at the largest aero- 
plane factories. Their work was. however, lim- 
ited to some extent by the exigencies of war, 
which confined them to the analysis and con- 
struction of only the types of aircraft which 
were being considered for production. 

It did not, to any extent, bring about the 
combining of the best characteristics of different 
machines of different countries, as might have 
been expected; nor did it bring about to any 
extent, the adoption of best engineering prac- 
tice in aircraft construction. This was due to 
the fact that the problems of aeronautic en- 
gineering were too complex to be mastered 
within a year, even by the best engineers, and 
the necessity for lightness in construction did 
not permit the adoption of automobile or naval 
engineering practice. 

War Developed Speed Regardles* of Flying 
Efficiency 

While collectively the developments in aero- 
plane construction brought about by the war 



N-C-1 F-LYING BOAT 



P-5-L PLYING 50AT 




SUNDSTtDT-HANNEVIG 



H-S 2-L FLYING 5OAT 



McCaughlin 



STATUS OF . \1MM.IKI) A KHONAt TU K\<;i\ KKKINt; 




I In- 



1 1 .inillrj -I'ajti- iMimlirr ri|iii|i|>nl with I Hull- Itny r motor-.. Our of the first l-inotiirrd planes In ! ]>r,>,lu.vcl. 

It w.i- luiilt in Great Britain. 



represent :i stupendous achiex cment. we- find 
tliat as :i whole tl;c \\;ir rcmiircmciits resulted 
in sacrificing Hying efficiency for high speed 
and fa-t climbing. Machines \\cre greatly 
overpowered and Mich important factors for 
peace Hying as slow landing speed and high 
gliding angle were overshadowed by the vital 
importance of fast climbing and speed. 

Night Bombing and Antiaircraft Brought 

About Valuable Developments in 

Aeroplane Construction 

The increasing range of the antiaircraft guns 
jWeed high flying and was responsible for the 
developing of high ceiling aeroplanes of light 
'construction and remarkable efficiency. The 
extension of night bombing operations brought 
ahout the construction of larger aeroplanes 
such as the C'aproni, Hand ley- Page, Vickers, 
A\ ro. etc. 1 

Tin- same thing was true in the construction 
of seaplanes. The need of Ion if distance air 
cruisers and torpedoplanes brought ahout the 
construction of large seaplanes, of which the 
\arious I'nrtiss types constructed in the I'nit- 1 
States and England are representative ex: m- 
pl- 

The war also brought about the construction 
of seaplanes capable of starting from and land- 

Kvolutinn of the Military \eroplnnc in thr " Textbook 

of Military \.-ron uitirs." published h\ tlie ('ntim ('... \. Y. 

r ntii>n of Marine Flying, " TcxtlvKik of Naval 

\T,,n.nti, s." publish) by the Ontury Co X. Y., for detailed 

lii-tory of thf evolution of seaplane construction. 



ing on fairly rough seas. This development is 
of great importance for Hying for sport, pleas- 
ure and commerce. 

Engineering Advantages in Large Machines 

Large machines permit refinements in con- 
struction, such as tic use of hollow struts and 
hollow members, which is not possible in small 
aeroplanes. 

This has made it possible to increase the 
ratio of useful load by over ten per cent, and 
to get nearer the goal of economic aerial trans- 
portation. 

It is hardly necessary to point out that the 
old theories to the effect that large aeroplanes 
could not be constructed have been exploded. 
There can still be found misinformed people 
who hold that as the thickness of the wings must 
i'-crease in proportion to the span of the win 
there comes a point where the weight of the 
wings is so great that their lifting capacity is 
not sufficient to lift the machine from the 
ground. 

We have heard such foolish arguments, which 
for the past fifteen years, and up to the Sum- 
r-er of 11*17, were actually responsible for de- 
laying the construction of larger aeroplanes in 
the I'nited States just as the fallacious theory 
that if one of the motors of a twin-motored plane 
stopped the plane would spin around, delayed 
the advent of twin motored planes. They are. 
at present, to a smaller extent, delaying con- 
struction of very large aeroplanes. As a mat- 




STANDARD 'E -4 




THOMAS-MORSE 54- 1 



1 



VOUGHT V.E.7 




5E V 



McC&ughiin 



STATIS OF APPLIKl) AKKONAITK r.N(.INKI.HIM. 



t<T .it' t';ict. through tin- development <!' more 
efficient aerofoils, and perfecting (lit- const ruc- 
tinii of uings, it IN no\\ po-.sihlc to (il)tain wings 
capable of lifting oxer ten pounds per square 
foot while xveighing less than one pound per 
square foot ! 

Plywood Construction One of Most Impor- 
tant Developments 

Plywood construction ha* liecii one- of the 
most important developments of the past two 
years. 

Plywood permits, for instance, the making of 
the fuselage of an aeroplane in one piece, on 
a mold, eliminating the tedious, heavy, cxpen- 
si\c construction of former days, xxith its scores 
of wires and tiirnhnckles. 



Plyuoo.l ciiv.stniction of dilVi n nt parts of 
aero]. lanes \\iil I cromc ,',,!ier:d as soon as the 
vain of | lywood is understood. 1 

Types of Heavier Than Air Aircraft 

The main txp.'s of lieav ier-than-air craft an 

(1 ) The aeroplane 

C.'i The helieopt.-r 

(8) The ornitlK.pt. r. 

The I'. S. Army Technical Department's 
definitions of these types can l>e found in the 
Index, with other aeronautic nomenclature. 

The helicopter and the ornithopter were con- 
ceived earlier than the aeroplane. Leonardo 
Da Vinci designed an ornithopter or Happing 
wing machine in the fifteenth century. Prac- 

S*e Appendix for Chapter on I'lywoods and Veneers In Ano- 
plane t'on-l ruction. 




The Navy-Curtlss NC-1, the prototype of the Xavy-Curtlss transntlnntir seaplnnrs. 

\ n,.,,,lH-r of Interesting engineering features are incoVporat.-.! in the .l.>ipn in this machine. T,e pilot is l,K-ate,l outs 
ami ,1^, the hull. The tail unit is supported by outriggers, instead of being carried on the rear of the 1 ull, a. 

n in n flying txmt. 




HANDLEY PAGE O-400 









"A.C.E " 



LAW5ON MT-2 




sT.vrrs or AIMM.IJ.D AKUONAITH ENGINEERING 



tic-ally every ^rcat inventor including Thomas 
Kdison. OrvilK- Wright. Louis HIcriot, IVter 
Cooper Hewitt, Kniil licrlincr has. during the 
J);l.st tit'tci-ll \cars xiveil serious consideration tti 

the problem of building a helicopter. And v\c 
may t\|)cct oood results in tin- near future. 

Now that tfo<nl engines arc a\ailal.lc it is 
possible tn (mild machines capable of rising 
from and descending to tin- ground vertically. 

As I have stated in tin- "Textbook of Naval 
\ ronaiitics." the Danish pioneer aeronautic 
experimenter Kllahamcr baa shown me the 
photograph of such a c-raft in lii^ht. 

Status of Present Day Aeroplanes 

./(7y;////-.v ha\( reached speeds as jrrent 
as HiO miles an hour, have carried loads ranjr- 
inu' up to six tons and have reached altitudes 
up to :JO. .><)<) t.et. which is hi^hrr than the 



world's highest mountains, and nmre than 50 
passen^, T> |, ;1V| . I,,.,.,, carried m i.iie ill-lit. In 
l.ict the accc.inplislimeiits of aeroplanes have 
e\cee<|ed t he ex pectat imis e\ en of those to uhum 
the suh.ject of aviation has lieen a life study. 

In spite of these accomplishments, those \\\\<, 
can see the future of aeronautics from a hroad 
standpoint reali/.e that in so far as the construc- 
tion of an aeroplane is concerned, aeronautics is 
in exactly the same position to-day as the art 
f shipbuilding would he if ship boilden had 
(inly reached the sta^c of building racing boats 
and small yachts! 

Analogous to the racing boat we have the 

speed aeroplane. The War has necessitated the 

design and construction of small inaehiiu s. 
whose prime requisites \\ere jjreat speed and 
nianoL-uverahility to be Used for combat pur- 
poses. Several successful designs were worked 
out, especially on the other side. The small 




'I'lii- " i-Vlixstowe Fury," Uie Porte triplane tl> inir boat. This monster flying boat, thr larp-st in cxlstrncr. Is Hriti.-h 
mi- with Hritish rnfri'nrs. It is fitted with five Hnlls-Hoyrr " Knfrlc-s " rnfrinrs arrnnfml In tandem wt* and ant sinflc 
lii-r." l'r<i|M-llcrs in tin- tnndi-in sets are four-hladed. and the others two-bladed. Thr tutnl span of the wings It IJS 
M; the len(rth <if the fuselafre, 60 ft.; the height from keel to ring post, 27 ft 6 In.; and the total weight i3,4OO II. v 



sT.vrrs OF AIMM.IKD AKKONAITU 



11 




Tin- Tu in nintiirril l-'iirniiiii l>i|>l.iii< 



service Ix-tMri-n Paris and I-onclmi 
fnrtahle <-al)in. 



il oom- 



wing area and high landing speed of these planes 
make them suitable- only for \cry expert han- 
dling, and for enjoying all the thrills and stunts 
of expert flying for sport's sake. 

\\ arc | list beginning to liuild low priced 
aeroplanes which will represent in aeronautics 
the equivalent of the motor boat. There are 
already small aeroplanes with a wing spread of 
IS to 20 feet, capable of going at a speed of 60 
to HO miles per hour, traveling about '20 miles 
to the gallon of gasoline. These small planes 
represent in aeronautics what the motor boat 
represents in the marine field or what the Ford 
and Dodge cars represent in automobiles and 
will be powerful factors in popularizing avia- 
tion. 

Hut as regards large aeroplanes. \\e have only 
in to build the equivalent of small yachts 
and to go beyond this brings up a large number 
of problems. 

The Navy-Curtiss Flying Boats have a wing 
spread of J-jf, feet; the chord and gap of the 
planes are !'_' feet. The machine is driven by 
four Liberty engines of 400 h.p. each. A speed 
of over 80 miles has been made, and in ten 
minutes the machine has ascended to a height 



of 2000 feet. Fully loaded this mac bine weighs 
28.000 pounds. It can carry a useful load 
amounting to more than six tons. A more 
comprehensive idea of its carrying capacity may 
be had from the fact that, on one trip .)() people 
have been carried. 

While there are several planes under con- 
struction at the date of writing which have a 
wing span of up to 100 feet, the \C type sea- 
plane and the Ilandley-Pauc aeroplane may lie 
said to approach the limit in biplane construc- 
tion. It is apparent that to double the si/e of 
the XT it would be necessary to find a new way 
of distributing the surfaces to lift such a large 
flying boat. 

The four-motored Ilandley-Page air cruiser, 
which can carry 4' | is and which nas 

given some fine demonstrations, is about l.'iO 
feet in span. It is apparent also that this type 
of plane could not very well he double:! in si/e 
without devising a different method of distrib- 
uting the amount of surface requind to lift a 
machine of such proportions. 

Caproni has built a 5000 hor-e powered tri- 
plane and is now working on larger planes. 
He has gone further in experiments with tri- 




Detailed Views of NC-4 Transatlantic Type Seaplane 



1 Forward part of hull. The ladder leads to pilots' cockpits. 

3 The commander's cockpit at the extreme front of the hull. 

5 "Wing tip float under the lower left main plane. 

7 The hiplane tail group. There are two fins and three rudders. 



2 One of the power units, showing streamline engine nacelle. 

4 The pilots' compartments showing special compass installation. 

6 Pilots' compartments as seen from the front, showing windshields. 

8 Side view of front of hull, showing placement of the navigator. 



sT.vrrs or .MMM.IF.D AF.KOX.UTU KN^INKKKIM; 



fummmiinii 




Ilir \I.-irt.ii "Mini- Mini" ,,,,,1 tl,,- \larlin " I ..,-],. " \ niM |, N , ,, M . ,,.,;_ ,|,,. ,,,,. () \, m . ri , an ,,,-n,HMiili.' <-n 

ftaeer. II., " Kin,- Mini" has wi,,i..s ,,,,h Is ,,., , ,,|,. ; ,,,,| ,, nh u ,,.,,,, ..,, ,,, s _ wi((| . m(i||ir ^.^ ^ |if (|| h ^ |( wi|| ( ^ 
,.n nu , Mimtry r,,.,,l ,n,l p, ,,|,,,,il .'n mil.-s ,, L ..,||,,,, ,,f ^.M.li,,.-. II,,. Martin " l-:,,|rlr " is <-<|iii|,|-,l uilli tv,, IIKI kp I . 

''"- i "" 1 is r;lt " 1 '" ' ; ' rr > ' l ""- " ( "--f"' l " ; " 1 "'' ( " IW ., rmisinp r;i.lin> ,,f OTCt .'"'Mi mil,-,. M,,tl, i,,arl,in. ,'- 

bet of renwrkaMe n-- engineering f.-,(nr,-s iii<-|inlin K tin- K-l.ar ,-,-llul,- truss, tlie retractable c-hawiis, ,-tc. Tli,- \ arf , r m...-liiin- has 

i drive truumiMion t,, UK- |ir,i|>,-ll,-rs. 



plain--, tlian ninst ul' tl.c o!ln-r (lesion, -rs and lie 
f ln-rd'uiv lias : antarc s i;i that direction, 

lint in plaiinintr his larger | l.iin-s !:< als. finds 
it necessary to ado;>t diilVn-nt | rincipK-s in ciis- 
pMsin-r of the enonni>"s an u m ,-i ssary to oh- 
tain the desired lii't he will ha\e tandem tri- 
planes. 

In order to hrin^ the aeroplane up to tin- 
standards set I iv iiiarini- einistruetors. we must 
de\elop a earjro earryin^ tyj-e of plane. It is 



(Mivions that the eoiiiinereial value of this type 
of niaehine is enonnoiis. Although we do not 
hope, at least for the pre-ent. to en-ate machines 
eapahle of carrying as iniic-h load as an ocean 
goin^r steamer, we do require a (ilane that will 
carry a sufficiently heavy load, which, taken to- 
gether with the \ast saving in time, will make 
the final tonnage transported close enough for 
coiiiparisiui. 




; 




The Ctlt-nn I.. Martin twin inotornl hiplnnr, r<juipprd with two Liberty ni,,t,>rs. 



Getting the same Engineering Results by Different Distributions of Wing Area 



Bristol Triplane, Type Bracinar with 4 I'unia Engines. 



' 





The Pemberton-Billing quadruplane. Designed by the English aeronautic enthusiast. The height of a machine of this type be- 
gins to be a serious problem, both in landing and in housing it. 




Experimental Tandem Biplane of ( olli.-x Jeans.m. View of machine taking off. Wing area, US sq. meters Span -X meters 
It is equipped with i motors of 300 h.p. each. Weight of machine, 3700 kilos. 



14 



STATt'S OF APPI.IKI) AKKON.U TIC \-.\C, I N KKHI N(. 



HANDILY PACE: BIPLANE: AB.E-A 1.648 5 r T 
/PAN - UPPER PLANt WO FT -LOWIS.70F-* CHORD IOF7 



SHADED AHCAS 
INDICATE T^ 
LOWfcR PLANE- 



-A ( 




) A" 


CUBfUCl 


N-C-1 HYING 50 AT AEtA 
tE PlANt \16 F T -LOWtB.96 T- T 


J 
CHORD 1 


FT 
2PT 



BIPLANE- WITH AWING ARtA Of- 10.00O 

./PAN, E>OTH PLANtS. 171 FT CHORD 28*7 INCH fry 



-iow Can We Distribute the 10,000 Square Feet of Wing Surface Required to Lift 20 

Tons of Useful Load? 



For commercial success the aeroplane should 
e Iniilt to carry 'JO tons of useful load. 

How can the 1O.IMM) square feet of wing siir- 

e required to lift this useful load lie dis- 
rihutedf It would he absolutely out of the 
uestioii to think of constructing a monoplane 
f that area. Since experiments have shown 
ie most desirable winj; proportion is to have 
ie spun ahout six times the width of the plane, 
r in other words, the aspect ratio should be 
bout > to 1. This would mean that in order 

obtain 1(1.000 square feet of surface in a 
lonoplane. its surface would have to be 244.8 
.et in length or span, and 40.8 feet in width 
r chord. 

1 1' the same area is to be obtained in a biplane, 
rvinjr the .same aspect ratio or span to 
hord relation, our span would be 171 feet and 
'tc chord -_'K..) feet. It is claimed tHht when 
ir faces are superimposed the full lift is not ob- 
lined from all the planes. In the triplane the 
ft of the middle wing is somewhat decreased 
eeause of the interference of the plane above 
nd the plane below. Some engineers have 
ven gone so far as to claim that the middle 



plane ^i\es practically no lift whatever. This. 
of course, is a mistaken notion. Provided that 
the gap between the planes is great enough, each 
of the planes is as efficient as a monoplane sur- 
face. The middle plane gives a decreased lift 
when the adjacent planes are placed too close to 
it, for then the air flow is interfered with. It 
remains with the designers of triplancs and mul- 
tiplanes to determine the aenxlynamical effi- 
ciency of the aerofoil. 

Structural advantages are to be had in tri- 
plane and multiplane combinations and very 
often the disadvantages resulting in decreased 
efficiency of the wings are more than offset by 
the structural advantages gained. 

If we tried to build a triplane with lo.mm 
feet of surface it would have to be close ' 
feet high. 

Here comes the difficult problems of landing. 
We recall that the Avro triplane at the lioston- 
Harvard Meet, September. 1910, had the tend- 
ency of toppling over at the least cause. That 
machine established a traditional prejudice 
against triplanes and quadruplanes. But the 
height of aeroplanes has gone up ; and although 



16 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



MONOPLANE- 

./PAN 244.5 ?! 
CHORD 40.8 F-T 




BIPLANE 

yPAN 171 PI 
CHOP-D 



3 PLANED 



4 PLANE./ 1 



5 PLANE-./" 



-E -i- E-E 



./PAN 141 CHORD 23.5 /PAN 121.6 CHORD 203 JPM 109.2 CHOBD 18.2 

COMBINED MONOPLANES AND BIPLANES 



5 PLANED 



7 PLANED 1 



12 PLANED 




8 PLANED 

J'PAN 86.4 CHORD 14.4 



109.2 CHORD 18.2 ./TAN 92.4 CHOBD 19-4 ./PAN 7O.2 CHORP 11.7 

COMBINED BIPLANES AND 



TPlPLANf 

./PAN 141 PT 
CHOBD 23.5 PT 



10 PLANty 




Z5 PLANtv/- 






JTAN 92. A CHQKP 15.4 yPAN 77. 4 CHORD 12-9 ./'PAN 48.6 CHORP B.l 

COMBINED TRIPLANLV & QUADRUPLANE,/ 1 




17 PLANED 



QUADP.UPLANE 

yPAN 121.8 PT 
CHOBD 20.3 PT 



15 PLANE,/ 

63 CHORD 10.5 



-/"PAN 48.6 CHORD 8.1 ./TAN 59.4 F-T CHORD 9-9 FT 

MULTIPLANE COMBINATIONS 



the prejudice still remains, the height of aero- 
planes is increasing year by year. The Porte 
triplane is over 27 ft. 6 in. high; the Caproni tri- 
plane is over 19 ft. high, the Gotha-Zeppelin is 
21 ft. high, the Voisin triplanes are 18 and 19 
ft. high respectively, the Handley-Pages are 
from 18 to 20 ft. high; the Curtiss NC is 24% 
ft. high. 

Such a machine as* proposed would possess a 
high center of gravity and would be apt to over- 
turn on landing, due to inertia, unless the body 
and lever arm were of sufficient length to coun- 
teract this force. 

Then also we must consider that it would 
necessitate a hangar of unusual structure to 
properly house such a machine. This is one of 
the allied problems which come up when unusual 
planes are contemplated. 

When Handley-Page built his large biplane, 



in 1916, and adopted a ten-foot chord, instead 
of the conventional 6%-foot chord, he started a 
new development. He demonstrated the possi- 
bility of using a greater chord to solve the prob- 
lem of building larger planes without going into 
extreme wing spans or excessive heights. 

But while adopting a greater chord may be a 
partial solution in building an aeroplane with 
5000 square feet of wing surface, it does not 
afford -a practical solution in building a plane 
with 10,000 square feet of surface. 

We- must, therefore, turn to new sources for 
solution of the problem of distributing 10,000 
square feet of wing surface in order to lift the 
20 tons of useful load referred to above. 

The following table has been prepared to 
show how an area of 10,000 square feet can be 
disposed and divided into from 1 to 25 planes, 
each preserving the proper aspect ratio. 



STATTS OF AIM'TIKI) AKU< >.\ ATTIC F..\ ( . I M .1 .H I \(i 

Area Distribution, Wings with Aspect Ratio 
of 6 to 1 



17 



\iinilirr 
of 

Surl 

1 



-. 

i 

III 
11 
19 
l.t 
11 
l.i 

u 
II 

I- 
II 

.'II 
.'I 



lull 

Siirf.Kv 
(M|. ft.) 

III.IHNI 
.'..IHMI 

-VVMI 
.'.INK) 
I.'. '.i. 
l.l> 

1,111 

1.IMMI 



...... 

-- 
,,, 

400 

4JV 

I il 
416 
400 



l'h.ir.1 
( f.,-1 , 

I-..' 

I'M, 
I.-..J 
111 

11.7 
ll.li 

Kl.l 
9.9 
9.6 

9.1 

-.i 

8.4 
8.3 
8.1 



Sp.ni 

i;i .u 
iii.n 
ttU 

-i n 

7u..' 

H i 

MM, 

39.4 
57.6 

.'.I. i. 
41.0 

IM 

i- ii 



It is noticed that in flic larger aeroplanes the 
aspect ratio tends to increase. Fur example, 
tin Handli-y-1'a.ne lias a ratio of 10 for the up- 



plane and 7 Tor tin- lower. Tins IN true als,, 
of tin- Caproni Triplaiu- \\lu-n- the aspect ratio 
of all three planes is aliout Id. Where : , on-atrr 
aspect ratio i<, under consideration land the 
trend of design in lary;rr machines leads us to 
the adoption of greater spam a different tal.l. 
of dinieiisions. would, of course, he necessary, 
hut the one sho\\n ahove ^i\<s us a working 
liasis. n| mi \\hieh calculations of a more exact- 
ing nature may he founded. 

Relation of Gap to Chord 

Tlie proper relation of gap to chord is 
greatly a matter of opinion. Authorities .i 
agn-c on how close win<;s can IK- placed without 
mutual interference. This is true c\en in tin- 
rase of triplanes. Manufacturers like Caproni. 
Aimstron^-Whitworth. Hoe and Curtiss ha\e 
conducted experiments with triplancs and ((uad- 
rupIaiH-s. hut it is a fact that very little aerody- 
namical data is available covering the results of 
tests on triplanes. quadruplancs, and multi- 
planes. 

Kvt-n at this late date many people will con- 
tend that triplanes and <|iiadruplancs are ineffi- 
cient hecaiise the middle wings do not lift. It 



I PLANf JPAN 344.6 PT CHOB.D 40.8 F-T 



2 PL*Nfr.T 



I7I.O 



CHO&D 38.5 ft 



3 PLANED ^PAN I4I.O 
CHODD E3.5 PT 



8 PLIkNtr /PAN S6.4 
CMOD.D W.4 PT 



L 



_L 



15 PLANE/ /PAN 63 PT 
CMOCD KX5 r! 



4 PLANt/ /PAX 121.6 f- T CHORD 2O.3 PT 



18 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Latest type of Voisin 4 motored 900 h.p. Biplane. 



is hardly necessary to point out that if the mid- 
dle wings do not lift, the trouble must be that 
the engineer did not get the best proportion of 
gap to chord. 

Another reason why a loss in efficiency may 
be found in triplanes and multiplanes is that no 
modification of the wing curve may have been 
made according to its particular application. 
When a monoplane wing section is to be em- 
ployed in a biplane arrangement, changes might 
be made in the contour of the under surface of 
the upper plane, and the upper surface of the 
lower plane. In the triplane, alterations should 
be made as in the biplane and furthermore, both 
upper and lower surfaces of the middle plane 



must be changed to coordinate with the plane 
below. 

With experiments along this line, more effi- 
ciency can be expected in the multiplane of the 
future. It is not to be wondered at that so 
little success has met the efforts of designers 
who sought to employ a "universal wing curve," 
having, they believed, a constant effect whether 
used as a monoplane, biplane, or triplane, de- 
ducting 5 or 10 f /r for multiplane inefficiency 
without suspecting that an alteration of the 
curves would give more desirable results. 

It may be found that altered wing curves 
permit of closer spacing between planes, tend- 
ing to cut down both the weight of interplane 




The DeH.-17, a twin motored Tractor Biplane. This machine has been designed for high speed passenger and freight 
service. The saloon will accommodate 14 passengers, each comfortably seated, having a clear view in all directions, and free 
to move about. Lavatory accommodations are also provided. The motors are of 600 h.p. each. The machine is capable of 
making a speed of 125 m.p.h. and has a radius of 400 to 500 miles at full speed. It can climb to 10,000 feet in 15 minutes. 



STATl'S OF APPI.IKI) AERONAUTIC KMJ1N KKH1NC 




Thr 1 r. n. li C.iiiilrini " \i-rnlui> " wliidi is , Mi-nun: p i~. HL-. -r. U-t,,- n I'.irU Mini l.iniiliin. Thr .' 'nu|.ir> arc rnrlosed in strcain- 

Im. .1 n.i.-.-IIrs in .iril.-r In drrrrusi- Hi.- resistance. 



struts ;iii(l bracing :iiiil tin- resistance they pre- 

.SCllt. 



of finding proper relation between the gap and 
chord, distances between sets of planes and of 
the reduction to a minimum of parasite resist- 



Tandem Planes Represent the Solution a nee. 



Thr lirst possible solution tllilt suggests it- 

sell' is that tin- 10.000 square I'cct of wing sur- 
face lie distributed in Tandem Plant's. Hut 
what should the Tandem Planes he? Mono- 
planes' Hi|. lanes.' Multij Liu's? 

Tlie first noteworthy experime its with Tan- 
dem plains \\cre made by Sainucl P. Lan^ley. 
Sinee'then a nuinhi-r of experiments have been 
made with tandem planes hut few of the experi- 
menters have had the opportunity of testing 
triplanes and ffettin^ aenulynamieal data so as 
to ascertain the relative efficiency of Tandem 
1 Manes. This is a tremendous field and here 
the aeronautic engineers will have to find the 
correct relation between surfaces that are dis- 
posed one above the other and in Tandem 
Planes, the distances between the planes or 
groups of planes. If three or more sets of 
planes are to he used, then the problems multi- 
ply. for. then will come in again the problem 



Problems of Trussing and Bracing 

The employment of many lifting surfaces, 
either superimposed or adjacent, will necessi- 
tate new structural methods. In this field, our 
engineers and bridge builders can help us. \\Y 
need the simplest forms of structural stiffening. 
in order not to create too much parasite resist- 
ance. By dividing up our wing area into many 
small planes, the loading on each plane will IK.' 
comparatively light, and consequently it would 
seem that a light but sufficiently safe structure 
can l>e used for these wings. (See in Appen- 
dix article on the Evolution of Aeroplane Wing 
Trussing.) 

Body Construction 

We will assume that the distribution of the 
10.000 square feet of wing area necessary to lift 




\ C.iunt Hriti-li Flyintr Boat, driven by three motors a(rfrrr(tatin(f HMHI li.p. Thfc boat wa* used by the British at Helip.l.ui.l 
I.itrlit for patrol duty It lias a larfre rruisin(r radius and rnn carry a considerable load. A reconstructed plane of thin type 
will tnaki- a jrixHl type of commercial passenp-r and freight carrier. 




The interior of a Handlev-Pape, electrically heated passenger carrying biplane used for regular passenger carrying air lines 




The " Braemar" Mark II Bristol Triplane, driven by four 400-h.p. Liberty Engines. It has a wing span of 82 feet, and carries a 

useful load of 8,000 Ibs. 
20 



STATl'S OF Al'I'I.IKl) AKRON ATTIC KN<; I N KKRI Ni. 




llritMi Ariiistn.ntf WhiUnrth 
l.'ii.iilrii|,|.nit- uill. a I in ti |> I 
i ML'im- It is ii two s.-atrr, jfrnrral 
utility lu.K-liiiif ntiil inakrs a spi'<l 
i -I in |>.h. nt (rround Irvrl. This 
wait onr of the first quadruplanes to 
l.< l.uilt. 



JO tons o!' cargo has been successfully worked 
out. At this point we art- confronted liy an- 
other serious |>rol>Icm. I low arc we going *" 
construct a body or fuselage for this Multi- 
plain-' We must provide spaces for the cargo in 
such locations as to make them readily access- 
ible, and at the same time to make the moments 
ahout the center of gravity of the whole machine 
either comparatively small or else nicely cmial- 
i/.ed. in order to prevent undesirable flying de- 
fects. The problem of furl storage is also pres- 
ent. The machine would be multi-motored, and 
the location of these motors and tin ir fuel sup- 
plies will involve a large amount of careful plan- 
ning. 

Furthermore, if our plane is to be a passenger 
carrier, comfortable (|iiarters must be provided. 
Hire again \\e must try to emulate the stand- 



ards of yacht and ship builders. We should 
try to locate our passengers so that they could 
obtain an unimpaired view, since the latter is 
of the supreme joys of an air voyage. 

The type of multiplane will also involve proh- 
l< ins. If it is to be a flying boat type, it must 
be made strong and seaworthy, and at the same 
time not unduly heavy. If we are planning a 
land niaehine, the landing gear must he propor- 
tioned to wi'hstand the heavy loads with a good 
factor of safety and yet not offer too mueh air 
resistance in flight. 

There follow herewith the designs and details 
of construction of practically all the important 
types of aeroplanes in existence to-day. The 
engineer is, therefore, enabled to compare them 
and see what the l>e.st aeronautic engineering 
practice of different countries is. 




Sikorsky I i|i|ane r<)ui|>|-ci with 4 Argus motors of I4O h.|>. rnrli was tin- |>n>tuty|H- of the iiiiilliiituloriil plane*. 



22 



TKXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




This 1917 Sikorsky biplane was equipped with 4 Renault motors of -'-0 h.p. each. It was built in Russia. 




A 5-motored German Giant Biplane. In the nose of the machine is an engine driving a tractor screw. The other four en- 
gines are mounted in tandem sets of two. A machine of this kind represents a possible type of commercial aeroplane of the im- 
mediate future. However, it can readily be seen that the proportions of a machine of this lifting capacity are approaching a 
limit. Some other method of distribution of the aerofoil surfaces is needed to obtain a still greater lift. 




A view of the Forward nacelle showing the covering of the 
front motor, the radiator mounting, etc. The observers have an 
excellent view, both ahead and behind. 




The two sets of tandem motors in the German 5-motor 
Biplane are mounted on long engine bearers. They dri 
their propellers through gear boxes. The cutting-out of t 
trailing edges of the wings for pusher propeller clearance 
thereby avoided. The importance of using geared drive f 
weight carrying aeroplanes has been fully demonstrated. 



CIIAI'TKH II 



MULTI-MOTORED AEROPLANES 



The 5-Motored German Biplane 

Complete details of this m.-irliinr ;irc not axailable at the 
present time. Tin- wreck of our of (lie bombing machines 
of this type \x is can fnlly studied by members of (lie Brit- 
ish Technical Department :iMil :in approximate idea of its 
construction xvas obtained. 

Tin- power plants are arranged as follows: In the nose 
nf the inachiiie is one engine drix ing n tractor screw. On 
each side of the fuselage, supported by the wings, is a long 
pair of engine hearers, carrying two engines apiece, which 
drive tractor and pusher screws, in a manner similar to 
that employed in the earlier designs of the Russian giant 
plane constructed by Sikorsky in I!IM. 

The engines used are the Max bach 300 h.p. standard 
ti-cy Under \ertical type, driving the propellers through a 
\-i>\ and driving shaft. This necessitates the employ- 
ment of a My wheel on the engine, to which is added the 
female portion of a flexible coupling. 

The .rear box casing consists of a massive aluminum 
casting provided with four feet which are bolted to the 
engine 1 carers. 

Two kinds of gear boxes are employed. These differ 
only in oxer all dimensions and the length of the propeller 
shaft. 

The larger type is used for the pusher screw in order to 
obviate the necessity of cutting a slice out of the trailing 
I the main planes. 

In each case the gear reduction is 21 41. 

Plain spur pinions are used having a pitch of 22 mm. 
and a width across the teeth of ~."> mm. The diameter of 
the smaller of the driving pinions is 162. ."> mm., and that 
of the larger pinion 282 mm. 

The larger pinion is considerably dished, but the web is 
not lightened by any perforations. 

The oxer-all dimensions of the longer gear box is as 
follows: 

I .u-th. Iii2.'> mm. 
Hreadth. 673 mm. 
Height. .">.'<;> mm. 

The driving pinion runs on two large diameter roller 
bearings carried in gunmetal housings supported in the 
inner end of the gear box. This part is split vertically, 
and united by the usual transverse bolts, whilst the conical- 
shaped portion of the box is solid. The usual oil-thrower 
of helical type are fitted. 



23 



At its outer end the pinion shaft terminates in a ring of 
serrations which engage with serrations provided in the 
male portion of the flexible coupling, these two parts Ix-ing 
held together with bolts and clamping plates. The engine 
is thus close up against the gear box. in contradistinction 
to the design of the (-engine power plant. There i* pmr- 
1 1< ally no external shaft at all. The larger pinion is 
mounted on a hollow shaft of !'.' mm. diameter, carried on 
roller bearings at each end for radial load and furnish- d 
at the nose end with ball thrust hearings. 

In the shorter type of gear box the larger pinion shaft 
is left solid, and it would appear that the gear box casing, 
instead of being made in three pieces, is made in two 
pieces, i.e., the whole box is simply split vertically. 

The smaller pinion shaft projects right through the gear 
box, and at its outer end carries a projection fitted with a 
small ball thrust race. This projection acts as a drive for 
the oil pump, which is mounted on the oil radiator used in 
connection with each gear box. 

It is worthy of notice that the German designers have 
fully realized the importance of using geared engines for 
weight carrying aeroplanes, and are apparently satisfied 
with the external gear box principle, although in this case 
they have made it a very ponderous affair. Needless to 
say, a great amount of the weight could have been saved 
if 12-eylinder engines had l>ccn used instead of 6-cylinder. 

The weights* of the gear box and its attachments are an 
follows: 

Gear box, long type. HO Ibs. 

Fly wheel and female clutch, 11 Ibs. 

Male clutch. ;. Ibs. 

Oil radiator, 12" L . Ibs. 

This, it will Ix' seen, represents, an additional weight of 
considerably more than 1 Ib. |x-r h.p. 

The oil radiator used in conjunction with each gear box 
is of a roughly semi-circular shape, and is slung under- 
neath the main transxerse members of the engine bearer* 
so that it comes immediately beneath the large feet of the 
gear box. This radiator is entirely of steel construction, 
and embraces 65 tubes of approximately 20 mm. internal 
diameter. These are expanded and sweated into the end 
plates, to one of which is fitted a stout flange, against 
which is bolted a small gcnr pump which constantly circu- 
lates the oil from the gear box case through the radiator. 

This gear pump is driven by a flexible shaft from the 
small pinion, the shaft and its easing being in all respects 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




similar to those employed for engine revolution counters. 
This flexible drive is taken off a small worm gear. 

Underneath the oil pump of the gear box proper an elec- 
trical thermometer is fitted, which communicates with a 
dial on the dashboard. 

It is a little difficult to see what object can be served by 
this thermometer, unless it be to indicate the desirability 
of throttling down a little in the event of the oil getting 
unduly hot, as there is no apparent means of controlling 
the draught of air through the oil radiator. 

Fitted on each gear box and working in connection with 
the oil circulation is a filter. This is provided with an 
aluminum case and a detachable gauze cylinder through 
which the oil passes. 

The arrangement of the gear box is such that the axis of 
the propeller is raised about 220 mm. above that of the 
engine crankshaft. 

The construction of the long engine bearers is not with- 
out interest. Each bearer consists of a spruce or pine cen- 
tral portion, to which are applied, top and bottom, five 
laminations of ash. On each side are glued panels of 
3-ply, about Vs in- thick. 

The engine bearers taper sharply at each end. and 
are strengthened by massive steel girders under each gear- 
box. 

The screws revolve at approximately half the speed of 
the engine, and having therefore a moderately light cen- 
trifugal load to carry, are made of a common wood that 
would scarcely be safe for direct driving screws. The 
diameter is K.'iO meters and the pitch 3.30, for the pusher 
screw, but it is not possible to state whether the tractor 
screws are of the same dimensions and pitch. 

The construction is very interesting; each screw is made 
of 17 laminations of what appears to be soft pine, and 
these laminations are themselves in pieces, and do not run 
continuously from tip to tip. They are, of course, slag- 
gered, so that the joints in successive layers do not coin- 
cide. Two plies of very thin birch veneer are wrapped 
round the blades. The grain of this veneer runs across 
the blade instead of along it. It is difficult to say from 
the appearance of the screw whether this veneer has been 
put on in the form of 2-ply or as two separate layers, one 
after the other. 

The engine control consists of five stout steel tubular 
levers. The levers are fitted with ratchets, so that each 
one can be operated individually; but the presence of the 
large-diameter toothed wheel in the center of the lever 
shaft would seem to indicate that all five levers could, 
when desired, be controlled simultaneously. 

The Douglas type of engine, carried for the purpose of 
driving the dynamo of the wireless and heating installa- 
tion, is used. The engine is a very close copv of the 
2% h.p. Douglas and is made by Bosch. The flv wheel 
is furnished with radial vanes which induce a draught, 
through a sheet-iron casing, and directs it past cowls on 
to the cylinder heads and valve chests. 

The generator is direct-driven through the medium of a 
pack of flat leaf springs, which act as dogs and engage 
with the slots on the fly wheel boss. 

An apparent transformer, used in conjunction with the 
wireless set, was also in use. 

The tail skid of the machine is built up of laminations of 



MULTI-MOTORED A KUOl'l.A \ ES 



25 



jisli and is furnislu-il with :\ lieax y s|< < 1 slim- .unl .1 large 
unixersal :itt;iflinii lit. 

The 4-Motored Voisin Triplane 

In order to axoid eonstructiiii; a machim >! huge pro- 
portions in order to obtain the desired lift, tin- French 
haxe taken a step in tin 1 riylit direction in distributing into 
thriv planes thr necessary aerofoil ana. 

Tin- Voisin triplanes .-in- an example of this type of 
machine. They arc powered with four motors, operating 
in a manner similar to those on the Handle] 
chine. The tail is supported liy streamlined oatn_ 
as shown in tin- illustration In-low. 

The 4-Motored Handley-Page Biplane 



This Iriijc niai-hiiii- was designed by Mr. Joseph Hand- 

.11 Kn^lish aeronautic engineer of over ten v ears' 

experience. It is powered with four Itolls-Koyce or Lib- 

erty motors, mounted in pairs. one liehind the other and 

driving tractor and pusher screws. 

The niacliiiie is capable of carrying more fuel and use- 
ful lo .-id than would In- required to cross tin- Atlantic 
In November. l!Ms, forty p isscngers were car- 
ricil o\i r the city of London in a maeliine of this type, and 
a month later a flight was made trout London to Cairo 
and from Cairo to Delhi. India. These demonstrations 
established this type of plane as a longdistance passenger 
and mail carrier. 

The 4-Motored Sikorsky Biplane 

The originality and energy of the Russian aviator and 
inventor. Mr. I. I. Sikorsky, made him one of the pioneers 
in the design and construction of huge, multi-motored bi- 
planes. 

In the sprinsr of 1913, his first giant aeroplane was 



ready to lake the air. II. called it the " Uiissi.m Knight." 

In general arr in-einent. the " Kiiss, HI Knight" was 

ch iraeli ri/t d ly a xery hm^. shallow liody. nliotit IS) 

in- It rs in h iiiilh. nhoxe which the cahin portion extended 

for a conaiderable distance. Tin ~p.::i ot its win^s is 

'' rs with a chord of :i meters. A monoplane tail 
and four vertical rud.h rs constituted the (nil units. 

The cahin portion of the mai him- forms the most inti r- 
eslin;; feature. It was dixidrd into three compartments. 
In the front one wen t.. s, ,ts. ..n. on e-i h sid, (if the 
cahin, in front of which were the dual controls. \.ir 
mally the controls on the hit win- the main ones, and in 
front of them were mounted all the various instruments. 
Between the two s,,ts was an open space hading to n 
door opening out on to the open part of th< hody in the 
extreme n.-si I-' nun here observations could l>e made 
with ease, as the position was so far forward ns to Ix w. II 
clear of all obstructions. For use at night n searchlight 
was placed right o:it in the lx>w, where it would not ila/./li- 
(lie pilot but would i'luminatc the landing ground. 

The central portion of the cabin was set aside for the 
accommodation of pass, M-, rs As was to be expected in 
a machine so elaborately equipped, the passengers were 
not asked to si|ucc/c into seats of the ordinary bucket type. 
Chairs, well upholstered and not fixed to the floor were 
pi -iced alongside the windows. Communication between 
passengers' and pilot's cabins was by means of a glass 
door, and thus any passenger could walk through the 
pilot's compartment out on the <>|>cn front portion of the 
body, where a more unobstructed view was obtainable. 
From illustrations, the doors leading out into the open 
appear to be. instead of sliding, of the swinging pattern. 
so that opening them against the pressure of the air may 
have been attended with some difficulty. 

To the rear of the passengers' compartment was n par- 
tition, with a door leading to the aft cabin, which was 
divided into two parts, one part of it being set aside for 
housing spare parts, while the other contained a sofa on 



X v- 

x 





The t- toreil Voisin Tri|>liinc. The rec|iiire<l aerofoil nrcn has been distrilmtril into tlirec j. lanes, therrl.y l.riiniiiiL' tlic 

|>ni|ii>rtii.iis c,i (lie whole machine to a reasonable standard. 'l"h<? 'necessary vortical surface has been obtained by constructing 
:| well between tile two sets of motors. The landing gear la of the vehicle tyjM-, enabling the machine to easily tr.m-l over 
Die ground. 



26 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



TWO 300 H.P. MAYBACH ENGINES 

_ SPANI; 






which those weary of the journey might lie down and rest. 
It is stated that the cabin walls so reduced the noise of the 
engines that conversation could be carried on quite com- 
fortably inside the cabin. 

In front the body rested on the lower main plane, which 
further supported the four Argus motors of 100 li.p. each 
that supplied the power. At first these four motors were 
mounted in pairs, one pair on each side of the body, the 
front one driving a tractor screw and the rear one a pro- 
peller. Later a different arrangement was tried by which 
the four engines were all placed on the leading edge, two 
on each side of the fuselage, and each driving a tractor 
screw. Later again the two outer engines were removed 
altogether, and the machine flew quite well with the re- 
maining two. After having done a considerable amount of 
flying and established a world's record for passenger 
carrying 1 hour 54 minutes with pilot and seven pas- 
sengers the " Russian Knight " came to an untimely 
end through a machine flying overhead shedding its en- 
gine, which crashed through the wings of the " Russian 
Knight." 

Immediately afterwards, Sikorsky began to construct an 



Three views of the German Zcpji 

improved type of giant. He finished his machine in De- 
cember, 1913, but to his great astonishment it refused to 
fly. After making certain alterations he succeeded in get- 
ting a very good flight out of it. This second giant was 
the famous " Ilia Mourometz." The span of its wing was 
thirty-two meters with a chord of three meters. The 
" Ilia Mourometz " presented a very peculiar appearance. 
The front of the body was flush with the front of the 
wings. The body and the under-carriage were constructed 
on an entirely different design to that of the " Russian 
Knight." The body instead of being completely made of 
three-ply wood was merely webbed with three-ply and 
covered with canvas. It had a series of cabins which ex- 
tended for a little more than half its length, after which 
a gangway led to the extremity of the tail, where a short 
ladder and trapdoor gave entrance to the tail deck. This 
deck was very small and was only used by the mechanics 
to regulate the tail plane and the rudder wires. The main 
deck was in the middle of the body and it was constructed 
to carry machine-guns and searchlights. A third deck 
was fixed to the under-carriage and here, too, there was 
room for a machine-gun or a searchlight. The aeroplane 



MULTI-MOTORED . \KKO1M..\NKS 



'27 



YO 300 HP. MAYBACH ENGINES 

:ET 




TIVO MECHANICS 

3OO H.R MAYBACH ENGINE 

GUNNER 



3OOH.RM4YBACH 
TWO MACHINE GUNS 




MACHINE 6UN 



LENGTH 72 FEET 



lin (-motored Moiiiliiiii: Biplane. 

had fi)iir landing wlicels. Sikorsky succeeded in getting 
much better n-sults from his second than from his first 
giant and during the spring of 191 -I he made many note- 
worthy Highls. The power plant consisted of four engines 
cl<M loped up to five hundred and twenty h.p. The speed 
of the aeroplane was about one hundred and five kilo- 
im-trrs nn hour and it could carry a load of two and a half 
tons, though as a matter of fact it rarely carried more 
tli.m one and three quarter tons. 

During the past two years, giant biplanes of the Sikor- 
sky type have been built in England, and equipped with 
Rolls-Royce motors; they have done excellent work. 

The 4-Motored Zeppelin Biplane 

The principal details of this machine were obtained by 
a group of engineers from the examination of a bomber 
brought down in France. 

Tin- pi me is equipped with four Maybach engines deliv- 
ering a total of 1-.JOO h.p. Each motor is independent. 
All are placed at the same level and in pairs. They are 
set i.p one behind the other. The front ones are tractors 



and the rear ones are pushers. F.ach motor is placed be- 
tween two braces. Half of the length on the motor ex- 
ti ink behind these braces, and half ahead of them. 

In order to bring the center of gravity of the machine 
sufficiently far forward, the weight of the two engines is 
massed towards the leading edge of the main plane; by 
driving the screws through shafts and reduction gears, tin- 
necessity of cutting away large sections from the planes to 
give room for the rear propellers has been avoided. Tin- 
two engines are placed close together, so that the rear 
motor is some little distance away from its screw. The 
forward engine is, however, mounted close up to the tractor 
screw. 

The employment of shafts and reduction gears nece-si- 
tates fly wheels on the engines. These are I ntrtrrs in 
diameter, and are made of cast iron. The tubular driving 
shafts between the fly wheel and the gear box are furnished 
with flexible leather couplings. These are of a novel ty|x-, 
and consist of a male and female drum, each furnished with 
circumferential notches, between which are interposed a 
series of flat leather strips. The female drum forms part 
of the flv wheel. 



Avion geant Zeppelin 

(Echelle 1/150<|. 






AVION GEANT ALLEMAND 




Bombing Plane. The 4-Motored Zeppelin Biplane. Drawings by Jean Lagorgette. 

The ribs of the lower wings and lower elevators are shown in dotted lines, also the rudders. To the left and out of the 
fuselage figures three and four show the diameter of the transversal struts. The upper wings are in reality 45cm. out of center. 
B and I are transversal frames. In G frame the wing longeron is placed somewhat underneath the position it occupies in !', and 
it replaces the tube cross bracing above frames E to H. The dotted lines indicate longitudinal beams, c is the sectional lon- 
geron of the fuselage, e is a section of the corner angle of the fuselage in the angle of the longeron. 




M./r i 






? Longueur tot*U..2 



Clponmirt Li 

t S.fO ff-W 

\'.DO ' 




A side view of the /eppelin Bomber. The upper wings are really out of center at the rear about 45 cm. The angle of in- 
cidence is such that the struts are at right angles to the chord. The propeller and motors are about 1-2 cm. back. The ribs of 
the central section are extended into the legs of AH of the cockpit. There are two elevators in similar directions and the cent nil 
section comprises a large triangle besides the lateral planes, the inside apex of which forms a semi-ellipse. The parts B-A in 
the sketch may be taken to pieces without spoiling the main part of the machine. 

28 



MlI/ri-MOTOKKl) Al.KOIM.ANKS 




\^^^^ 

i *t wni n i vr/*,* *, 

if ttt r*< M.IHI t 
.H,* t it* 

- ,- \QIAPHAWT* JHfftfft 

\n>** 



. : . 



Dia,;rii.iiiiiatic view of lln- constrii; lion of thr /.cp|tclin l-motorcd 



Iliplimc. 



Tlir ue.-tr li\ consists ot a casing i>f aluminum, prov ithcl 

With ffiiiljll^ f',11-.. 

Mi-ni-.ilh c. it-li i;r.-ir t-.iM i> .-i >in;ill r:uli:itor fur cotilin)! 
tin- liilirir.'itin-z "il cirt'ul.-ili il tlinri^li tin- rnu'ir-. This 
r-nli-ittir t-Kii-ists of ;i tl:it si-nii-cirt-ulnr tank, fitted with 
iruni-ro-.i- (T.-ITI-M r^t- Cil't--. .it fairly Inrj;c ilinmctcr ( about 
-,'n nun.) in a ni.uiiie r similar to that of n honryromh ratli- 
ntur. A pump Miiiiintcd at the linsr of the radiator is also 
ftirnislii-d with an electrical thermometer, giving a reading 
on i ili il in tin- ciu-kpit. 

i-iii;ini' !< fitted with a self starting arrangement of 

the tv|x- usually fitted tt> Mavhat-h motors. The exhaust 

pipe may he closed l>y mean-, of a shutter, and all the 

cylinders can l filled with gas from the carburettor by 

- of a large hand-pump, for whi;-h pur|x>se all the 

\al\es are held open. \\'ht n these valves are closed, and 

the starting magneto operatitl. the engine tires aiiil con- 

tinni-s running. Kach engine has its own radiator, whh'h 

is in united directly above it. and supported by stnts and 

'ires at a point about half-way In'tween the top and 

^i planes. These radiators are of the usual type. 

They are rectangular in shape, with their greater length 

placed hori/.ontally, and the radiating surface consists of 

i zig-zag tubes placed vertically. 

The engine hearers consist of stout ash spars, reinforeed 
with mulii-ply wood. The engine controls appear to be 
made chicHy of ash and covered with a thin veneer. 

Wing Construction 

Tin spars are built up very elaborately in sections, and 
consisting of no less than seven sections of spruce, rein- 
forced with multi-ply on each side, and finally carefully 
it! with doped fabric. 

The spars of the lower wings are continuous, that is to 



they run right across tile center section of the fusel- 
age, to the longerons of which they are secured, contrary 
to the usual practice, in which special compression mem- 
bers, forming part of the fuselage construction, are em- 
ployed. The wing surface, both upper and lower, is di- 
vided into three sections, of which the middle section ex- 
tends to the engine mountings on each side. Tl.i spars in 
this section are both at right angles to the axis of the 
fuselage. At each side of the middle section the leading 
edge of the wings is boldly swept back as well as tapered. 
The rear spars of the wings, together with those of the 
center section, form a straight line from wing-tip to wing- 
tip, but the front spars are swept back. 

Tin ribs are built up, and of girder form. 

Between the leading edge and the leading spar, numer- 

is extra ribs occur in addition to the main ribs. Internal 
bracing against drag takes the form of steel tubular com- 
pression members and steel cables, the former being placet! 
at a point coincident with the attachment of each inter- 
plane strut. An additional bracing is installed, of which 
the compression member consists of a double rib placed 
half-way between the struts. In each case the bracing 
wires pass obliquely right through the spars. 

The ribs are mounted parallel to the line of flight. 
The dis|>osal of the spars is as follows: 

Top Plant 

Leading eclfre to center of leading spar. . . 1 ft. 9i/ t in. 

Distance lietween centers of spurs i ft. ~'/in. 

Trailing edjre to center of rear mnin spar 5 ft. 

lloltom Plant 

1 .ratlin? edfrr to center of lending spur. . . 1 ft. TV, in. 
Distances U'twern centers of m.-iin spurs. 5 ft. I in. 

Trnilinjr edge to center of rear main spar 5 ft. (approximately). 

The trailing edge of this aeroplane was too badly dam- 
aged to permit of this measurement being given accurately. 



30 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




fofa/e 



>,t "00 



F,0. 3 eH. - Avion .n, Zm.ll* - E ^^,- ^ n ^Ti"^ n ^^^^^ ^'^ ^^' """ ~ ""* "' ""' 

Giant Zeppelin Aeroplane, al - duralumin; b wood; c- cable; f - steel cable; g- sheath; t tubing. 



Between the interplane struts the rear spars are thinned 
down in width, but their depth remains practically constant 
from root to tip. Such tapering as exists is so arranged 
as to promote a decided wash-out of the angle of incidence 
near the tip. This is done by tapering the front spar on 
its upper edge, and the rear spar on its lower edge. 

Ailerons 

These are on the top planes only, and are provided with 
a framework of steel tubing. They are not balanced, and 
the controls are led in the usual manner through the bot- 
tom plane from the aileron lever. 

The span of each aileron is 22 ft. 5 in., and the chord 
3 ft. 4 in. 

Inter-plane Struts 

These are of large-diameter steel tube, covered in with 
a streamline fairing consisting of three-ply mounted on a 
light rib-work of wood. 



Bracing 

The attachment of the bracing cables to the spars is 
somewhat similar to the bracing of the Fokker fuselage; 
that is to say, the wires, instead of being anchored at each 
end to an eyebolt, are double, and are looped round the 
spar, to which is fixed a grooved channel-piece for the 
reception of the cable. It is difficult to see that any ad- 
vantage is gained by this arrangement. 

Tail Unit 

A biplane tail, somewhat similar to that of the Handley- 
Page, is fitted. The fixed tail planes, the angle of inci- 
dence of which can be adjusted through small limits, are 
of wooden construction, and have the following dimen- 



Span each side of fuselage 12 ft. 4 in. 

Chord (average) 4 ft. 10 in. 

Gap 6ft. 9y s in. 




The Bristol Bomber Triplane Type "Braemar" with 4 Puma engines. The motors are mounted in tandem pairs. Ailerons are 

fitted to the ends of the two upper planes only. 



MULTI-MOTORED AKKoi'LANKS 




virw of the liristol 1-inotorccl llraemar Tripl.uie. The continuous middle wing over the fuselage is an interesting feature. 



Elevators 

Tin se arc fitted to both tlir top .-mil bottom tail planes. 
and ari ..( .iliiiiiiiiiiin construction. tin- rilis. being of girder 
form, sunn what similar in construction to tin ribs of the 
mum planes. Tin ili 'valors ari- not balanced; the top and 
l)ottom delators. are titled with independent control levers. 
lint arc prcsiimalilv operated together from the control 
.stick. Their dimensions arc ax follows: 



S|...n .............................................. -". 6 in. 

Choril ;.t lip ....................................... -'ft. tin. 

Chord lit center .................................... I fl. i". 

Fins 

There are three fins; two outer ones forming interplanr 
struts, and an inm-r central one of triangular shape. 



Rudders 

The framework of these orirans is hiiilt up of aluminum. 
There is also a quadrant nt the foot of the rudder posts by 
means of which the\ are operated; each rudder |K>st it 
fitted with ball bearings, both top and bottom. 

Undercarriage 

Beneath each engine section is an undercarriage consist- 
ing of a massive axle fitted with four wheels at each end. 
This axle is attached by india-rubber shock absorbers to 
the tubular steel V-struts which form extensions of the 
engine bearer struts. A third undercarriage is mounted 
under the forward pnrt of the fuselage, and consists of an 
axle with one pair of wheels. 




Photograph of the famous IV llnviland 10, which is being used in the London to Paris passenger service. This machine is 
equipped with two Koll.s-Hoyce motors, and has a maximum speed of 128 miles per hour. 




32 



MULTI-MOTORED .\KK< HM.ANK 




The I > \ ,.\ i urti-- No. I. (ir-t to cro-s tin- \tl.intic 



The U. S. Navy-Curtiss No. 4 Transatlantic Seaplane 



Tlii- \( Type of Hying boats constructed liy tin- Cnrtiss 
Cn!ii|i.iiiy. represent- strictly original American elcvelop- 
IM. tit. Tin- design was initial, d in the Fall of I!H7 by 
Rear Ailmiral I). \V. Taylor, chii-f constructor of the 
I S. \.-i\y. The big boats were designed for weight 
carrying and it was intended to use them in eomlritini; 
the submarine menace which had assumed alarmini; pro 
portions in 1!>18. The NC-1 was completed and given 
her trials in October. I'.US. Since that time the NC-2, 
\i ''. and NC-1- followed in quirk succession. 

Fully loaded the machine weighs 28,000 Ibs. and when 
empty ( hut including radiator water nnd fixed instru- 
ments .-mil equipment) l;>,K7t- Ihs. The useful load avail 
aMe for crew, supplies and fuel is. therefore, 12,126 Ibs. 
or oxer I-:! per cent. This useful load may be put into 
fuel, freight, etc.. in any proportion desired. For an 
endurance High) there would be food, v/ater, signal lights. 
spare parts, and miscellaneous equipment (52 } Ibs.), oil 
(7.10 Ihs.). and gasoline (!K5.0 Ibs.). This should suf- 
fice for a flight of 1100 sea miles. The radio outfit is of 
sufficient power to communicate with ships 2OO miles away. 
The radio telephone would be used to talk to other planes 
in the formation or within x'5 miles. 

The principal dimensions of all the NC Machines are 
as follows: 

General Dimensions 



Span, upper plane 1 36 ft. in. 

Spun, lower plane 91 ft. In. 

Chord I.' ft. in. 

Gap, maximum 13 ft. 6 in. 

Gap, minimum I -1 ft. in. 

I-ength overall 68 ft. 3% In. 

Height overall 34 ft. 5% In. 



Areas 

Main planes (including aileron-) 

Ailerons , 

Stiiliilizrrs 

Rudders 

Elevators 

Fins 



Of. /I 



905 



40 
79 



Angles 



tn hull . . 
Kn^ine- to hull . 
Staliiliftcr to hull 
Dihedral, upper . . 
Dihedral, lower 



3" 
0* 

r 

0" 
3 s 



Weights 

Pound, 

Machine empty !5,H?i 

Fully lomlrd iHjOOO 

Csefiil lo.id I 

Weight per l>.h.p 17.i 

Tank Capacities 



Gruvitv 


'/of/on* 
. 91 


Fuel 


1.800 


Oil . 


160 



Performance 

Knoll 

Speed rnnge for IHflM Ilis 74-58 

Speed range for J4/WO Ibs 84-53 

Main Planes 

Considerable research and experiment was necessary to 
determine the best disposition of material to adopt for 
wings of this si/e. The R. A. F. 6 curve is used. The 
structural weight of the completed wings is only 1 ' .. 
pounds per square foot, and they can carry a load of 11.7 
pounds. 

Wing spars are of spruce, box section. Ribs are made 
up of spruce cap strips tied by a system of vertical and 
diagonal strips of spruce. 

Each rib weighs but '2fi ounces. On test they were 
required to carry a proof sand load of 1AO pounds for 
21 hours without showing signs of weakness. 

The leading edges of main planes are hinged to permit 
accessibility to the aileron control cables, which run con- 
cealed in the wing. 

Interplanc struts arc of unusual construction. Tliev 
are of box section spruce, faired off to a streamline shape 
by -tiff fibre. To reduce any tendency of the struts to 



34 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




with 4 Liberty motors 



bow under load, the middle points are connected by steel 
cable. 

The metal fittings where struts and wires are fastened 
to the wings presented a serious problem. The forces to 
be taken care of were so large that it was necessary to 
abandon the usual methods of the aeroplane builder and 
adopt those of the bridge designer. All forces acting at 
a joint pass through a common center. In this case, as 
in a pin bridge, the forces are all applied to a large hol- 
low bolt at the center of the wing beam. In the design 
of the metal fittings to reduce the amount of metal needed, 
it was decided to employ a special alloy steel of 150,000 
Ibs. per square inch tensile strength. To increase bear- 
ing areas, bolts and pins are made of large diameter but 
hollow. 

The upper plane is in three sections ; center section 25 
ft. 6Vi> in. in span. Lower plane in four sections ; inner 
sections of the lower wing are built into hull. There is 
a clearance of ^4 inch between outer and inner plane sec- 
tions. 

Outer lower sections have a 3 dihedral; elsewhere 
plane sections are in flat span. 

Ends of struts supporting middle engines are centered 
50% inches apart. Between these struts the middle en- 
gines are located 6 ft. 10 3/16 in. above the center line 
of the front wing beam. The center line of the top front 
wing beam is located 6 ft. 7 15/16 in. above center line of 
nacelle. 

The outer engine nacelles are centered 10 ft. 6 11/16 in. 
from the middle of the machine, and 5 ft. 5 1/16 in. above 
the top of the front wing beam. 

The center engines are located 2 ft. in. higher than 
the outer engines. 

The span of the upper plane not including the aileron 
extensions is 114 ft. Ailerons on the upper plane are 36 



ft. long. Chord 43 in. At the balanced portion the 
chord is 6 ft. 1 in. Balanced portion extends 6 ft. beyond 
the end of upper rear main wing beam. Ends of ailerons 
project 15 ft. beyond lower plane. 

Chord of main planes 12 ft. Forward main wing beam 
centered 16 ] /i in. from leading edge; beams center 84 in. 
apart; trailing edge 43 1 /-; in. from center of rear beam. 

Hull 

The hull or boat proper is 44 ft. 8% in. long by 10 feet 
beam. The bottom is a double plank Vee with a single 
step, somewhat similar in form to the standard N'avy 
pontoon for smaller seaplanes. Five bulkheads divide the 
hull into six watertight compartments, with watertight 
doors in a wing passage for access. The forward com- 
partment has a cockpit for the lookout and navigator. In 
the next compartment are seated side by side the principal 
pilot, or aviator, and his assistant. Next comes a com- 
partment for the members of the crew off watch to rest 
or sleep. After this are two compartments containing the 
gasoline tanks (where a mechanician is in attendance) 
and finally a space for the radio man and his apparatus. 
The minimum crew consists of five men, but normally a 
relief crew could be carried in addition. 

The hull is designed to have an easy flaring bow so that 
it can be driven through a seaway to get up the speed 
necessary to take the air and a strong Vee bottom to 
cushion the shock of landing on the water. 

The combination of great strengtli to stand rough water 
with the light weight required was a delicate compromise, 
and it is believed that a remarkable. result has been ob- 
tained in this design. The bare hull, as completed by 
the yacht builder and ready for installation of equipment, 
weighs only 2800 Ibs., yet the displacement is 28,000 Ibs., 
or one-tenth of a pound of boat per pound of displace- 



MULTI-MOTORED . \KKO1M..\\K 




Tin- Nl I, transatlantic t\ |ie seaplane, powered liy four l.ilierly motors 



m< nt. Tliis lightness of construction was attained liy :i 
car, III! selection ;ili(l distribution of mat, rials. 

Tin- keel is of Sitka spruce, as is tin- planking. Longi- 
tudinal strength is thru liy two girders cif spruce braced 
with sti-t-1 wire. To insure w ater tightness and yet keep 
tin- planking Ihin. linn is a layer of muslin set in marine 
between the two piles of planking. 

The Hull is H ft. S-, in. in 01, rail length. Step is 
loeated _'T ft. 8 :! , in. from the bow. The stern rises in 
a straight line from the step in a total height of H ' _. in. 
The hull has a maximum depth of 7 ft. 5"^ in., and a 
maximum width of 10 ft. The leading edge of upper 
main plane is located 18 ft. 2 in. from the bow. 

Tail Group 

The biplane tail is carried on three hollow spruce nut- 

Front beam of upper horizontal stabilizer is MO 

ft. I I ' | in. from trailing edge of main plane. Gap be- 

tail planes. ;i ft. 3 in. The single lower outrigger 

from the hull to the lower stabilizer is attached to the 

stahili/.i r at a point 10 ft. 11 in. above the lowest point 

the hull. 

Span of upper elevator. .'17 ft. 11 in. The lower sta- 
bili/.er is 32 ft. in span. Knds of upper elevator project 
5 ft. I 1 ' L . in. beyond the lower stabilizer. The balanced 
portion of tile elevators is (i ft. ~> ill. in width. 

Tin- upper stabilizer is :t I ft. in span. I.ower stabilizer 

in span. Chord of both stabilizers .5 ft. 6 in. 
Vertical tins between stabilizer planes are loeated at 
ends of lower stabilizer. From these tins, rudders are 
Wnged, interconnected to balanced rudder situated at the 
middle of tail plane. 

The tail planes have a positive incidence angle of 2. 

Controls 

The steering and control in the air are arranged in 
principle exactly as in a small aeroplane, but it was not 
;s\- problem to arrange that this 1 1-ton boat could 
be handled with ease by one man. To obtain easy opera- 
tion, each control surface was balanced in accordance with 
expi rim, nts made in a wind tunnel on a scale model. The 



operating cables were run through ball Ix'aring pulleys, 
and all avoidable friction eliminated. Finally, the entire 
craft was so balanced that the center of gravity of all 
weights came at the resultant center of lift of all lifting 
surfaces and at the tail surfaces so adjusted that the ma- 
chine would be inherently stable in flight. As a result, 
the boat will fly herself and will continue on her course 
without the constant attention of the pilot. When he 
wishes to change course, however, a slight movement of 
the controls is .sufficient to swing the boat promptly. 
There is provision, however, for an assistant to the pilot 
to relieve him in rough air if he becomes fatigued or 
wishes to leave his post to move about the boat. 

Engines 

The four Liberty engines which drive the boat are 
mounted between the wings. At MM) brake h.p. per engine, 
the maximum power is 1600 h.p.. or with the full load 
of 28,000 pounds, 17.3 pounds carried per h.p. One en- 
gine is mounted with a tractor pro|-ller on each side of 
the center line, and on the center line the two remaining 
engines are mounted in tandem, or one behind the other. 
The front engine has a tractor propeller and the rear 
engine a pusher propeller. This arrangement of engines 
is novel and has the advantage of concentrating weights 
near the center of the boat so that it can be manoeuvred 
more easily in the air. 

A feature that is new in this boat is the use of welded 
aluminum tanks for gasoline. There are nine v2O()-gallon 
tanks made of sheet aluminum with welded seams. F.ach 
tank weighs but 7<i 11s.. or .:C. Ib. per gallon of contents. 
about one-half the weight of the usual sheet steel or copper 
tank. 

The face of the radiator for outer engines is I.", ft 
in. from the bow. The face of the radiator for the for- 
ward middle engine is lit in. back of the face of other 
radiators. The (enter line of central nacelle is 6 ft. 
5 1/16 in. above the deck of the hull. Above outer inter- 
plane strut the center line of front wing beam is located 
13 in. above the deck of the hull. 




V 








THE CAPBONI 

TYPE CA-4 1915 

TBIPLANE 

_/c.l of meter-/- 
' ' i S 



36 



MULTI-MOTORED A KROIM.ANKS 




I riphiin 1 , c.ijialilr of carr\ ini: 



ful loud of fi,(<)9 |I>S. 



The Caproni Bombing Triplane Type CA-4 



The ( aproni triplanc represents n type designed and 
built by the famous Italian constructor since 1915. This 
iii.-tchine was err atcd at th.it time for the night bombing 
of important military and naval bases, railroad stations 
and war plants. 

There are three motors, distributed on the two fuse 
lages and on the central nacelle. The central motor is 
tor a pusher propeller, while the two lateral motors have 
i i. li a tractor. Both tractors turn in the same direction. 

Fuselages and nacelle are attached to the spars of the 
middle wing. The center wing section, lower plane, holds 
the bomb rack. This bomb-dropping apparatus was also 
devised by Kngineer Caproni. 

Normally the crew of the maehine consists of two pi- 
lot,, seated side by side, as it is usual with the Caproni 
bombing planes, a gunner in the front nacelle cock pit. 
who operates a 1 ' ..-inch gun and two Fiat machine guns, 
coupled on the same mount. The front gunner also oper- 
ates a searchlight of the Sautter-Marie type. The rear 
defence is entrusted to two gunners, each of whom is 
seated in one of the fuselages; they also handle Fiat ma- 
chine guns coupled on the same mount. 

F.ach of the five men can move from one part of the 
maehine to another. Between the central naeelle and the 
fuselages on the middle wing a passage covered with 
r wood is installed for this purpose. 

The bomb sight and the five handles controlling the 
bomb rack are operated by the pilot on the right-hand 
si at. 

The CA-l triplanc has been successively equipped with 



three different ty|'s of motors. At first three Isotta- 
Fraschini 8-cylinder (vertical) 2-10/250 h.p. engines were 
used; it was later equipped with three Fiat A 14-Bis 6- 
cylinder (vertical) engines, and finally three Libcrty-12 
engines. Navy ty|x- (low compression) were adopted. 

With an aggregated useful military load of OOOO Ibg. 
the performance of this triplanc, equipped with Liberty 
engines, have IN-CII. especially in climbing, considerably 
better than those obtained with the other two types of 
motors. In the official tests, at full load and fully armed. 
a speed of 98 ni.p.h., registered at 65fiO feet, was reached. 
The average rates of climbing attained with Liberty mo- 
tors at full military loads were: 



frrt in li minutes 
6,560 fret in II minutes 
10,000 fret in .'. minutes 

The ceiling is at about 16,000 feet. 

The total weight of the machine, empty, is 11,100 Ibs. 
With full military load the machine weighs 17,7ml Ibs. 

With a complete fuel load of 550 gallons, the bomb 
rack is supposed to be loaded with 2500 Ibs. of bombs. 
but practically in almost all bombing raids the load of 
bombs exceeded SOOO Ibs. 

The following is a table of the general specifications. 

General Eimensions 

Overall wing span at trailing (edge) ........... 96 ft. 6 in. 

Overall height to top of aileron, lever in nornml 

position ..................................... 20 ft. 8 in. 

Overall length ................................. *-' ft. II in. 

Chord ......................................... 6 ft 11% In. 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A Caproni 3-motored Biplane in flight. The central pusher propeller, and the tail construction can readily be seen. Span, 76 
ft. 9 in. Chord, 9 ft. Gap, 8 ft. 9 in. Over-all height, 14 ft. 9 in. Over-all length, 40 ft. 9 in. Engines, 3 Liberty 400 h.p. 

Gap 7 ft. 13i/ 2 in. Main Planes 

Gap -r- Chord . ach of t , )e three p j anes ig bu0t up in seyen wing sec . 

Areas tions. The corresponding sections in upper, middle and 

EACH lower wings are equal in length. The wing spars are of 

SECTIOX ToT 'Y' box beam section. The ribs, double ribs and box ribs are 

Upper, middle and lower center section '1.413 U5.240 in white-wood and ash (cap-strip). Between rib and rib 

Upper, middle and lower inner intermediate the wing spars are wrapped with strong linen. The con- 
section 91.589 549.534 nection between the two subsequent sections is obtained 

Upper, middle and lower outer intermediate w j t ], t ] le ma l e an d f ema le box-fitting system. 

section 91.589 549.534 m, , . . ,. . . . . ,. .. . ~ -. 

The chord is. for the entire length of the wings. 6 ft. 

Upper, middle and lower outer section 130.282 781.692 

Aileron area 37.810 226.863 J 1 % m. The covering is of linen, nailed on the rib cap- 
strips and on the leading and trailing edges. On the 

Total area 2,222.86: linen, above and below the wing, maple batten strips are 

Rudder 26.943 80.829 screwed in correspondence to the ribs. 

Stabilizer 109.752 . 

Elevator 81.614 * or tne mterplane struts, ash, spruce and seamless steel 

tubes are used. Some of the struts have adjustable ends. 
Detailed Dimensions The bracing is, as usual, with steel cables and wires. 

Upper, middle and lower center section length . . 5 ft. 6% 4 in. Gasoline System 
Upper, middle and lower inner intermediate 

section length 13 ft. iy lfl in. The gasoline is supplied by three tanks disposed ; two, 

Upper, middle and lower outer intermediate sec- one in each of the fuselages and one in the nacelle. Three 

tion length 1 f t. 1% in. wind-driven centrifugal pumps pump the gasoline from 

Upper, middle and lower outer section length. Wft % in. ^ ^ to & ^^ ^.^r, and from this to the 

Aileron ... ! 19 ft. 4i$ 8 to. carburetors of the three motors. The pilots have close 

Stabilizer length .34 ft. li% 2 in. at hand the devices necessary for the regulation of the 

Stabilizer breadth 3 ft. 12%,j in. gasoline pressure. For the testing of the motors on the 

Elevator length J Mil 8U? i g roun d two small gravity tanks are provided; these are 

Elevator breadth .. 1ft. l%\n. ' excluded from the circuit while the machine is in flight. 

Front strut height (average) 7 ft. 3^' fl in. Each of the three tanks is divided in three compartments. 

Rear strut height (average) 7 ft. 8i% 2 in. a nd at the bottom of each of said compartments a check 

valve is applied, this valve working so as to avoid that 
in the event one of the compartments is shelled -the gnso- 

ctT-r wing , c '7 d / I I de - S0 min ' line in the undamaged compartments should leak through 

Stabilizer chord minimum 3 deg. , , , 

Stabilizer chord-maximum 8 deg. the hole bored m the damaged one. 

Motor inclination 2 deg. Chassis 

Stagger deg. 

Sweepback deg. The landing gear is of a special Caproni design and 

Dihedral deg. very robust. The two M-struts are of laminated ash and 



MULTI-MOTORED .\KKOIM..\NKS 




A (':i|ir<>iii hyilroaeroplime cquip|tcil with three l-'int imitors of :K> h.|>. mch. 



spruce, wrapped with strong cam -is f ihrie. The chassis 
carries on r-irh side one front .-mil on<- rear a\le; these 
avlcs nre attached to the rh.-i-.sis by means of shock ab- 
sorlx-r rulilii-r curd .-mil rods fastened at the other end in 
n universal joint, so as to adsorb whatever oscillation the 
maehine IM.IV make in taxing or landing. Kach of the 
front axles carries two double wheels, one on each side 
of the M strut. The chassis is braced in the usual man- 
ner with double steel cables. 

Nacelle 

Tin- nacelle is perfectly streamlined (dirigible form). 
Two main longerons with compression steel tube struts 
bet u i en them and diagonal steel brace wire and cables 
form the frame on which a set of ribs of appropriate de- 
sign are fastened. The outer edge of the rilis determine 
the shape of the nacelle. Hirch veneer and walnut are 
employed in the construction of these ribs, said construc- 
tion In -ing of a manner similar to that employed for .similar 
elements of rtyin^ bo-its. The front of the nacelle, upper 
part, is formed by :i cowling made of plywood with in- 
terposed layers of fabric. 

The two pilots are seated back of the front gunner. 
1'chind, they h.ive a gasoline tank, and before them a large 
dasbl-o-ird for the instruments, while between them thev 



have board for the controls i gas. spnrk and altitude ad- 
justage) for the three engines. The gasoline system i 
controlled by various cocks and a special distributor, all 
disposed in such a manner as to render them easily acces- 
sible to either of pilots. In the rear of the gas tank, 
which is of the same circular section that the nacelle has 
in that tract, there is a short path that allows the mechanic 
free access to the rear motor. The engine bed in con- 
veniently braced with adjustable steel tubes and steel 
braces. The rear part of the nacelle around the engine 
is also cowled. For the remaining parts linen and veneer 
are used. 

Fuselages 

The fuselages are flat-sided and of the usual construc- 
tion with four ash longerons, and between them compres- 
sion struts, steel cables and wire bracing. All the fittings, 
to which the diagonals are fastened, can be manufactured 
with the same set of dies. They are extremely simple 
and light in weight, without welding or bracing, and are 
attached without drilling the longerons. The front end 
of the fuselage around the motor is aluminum cowled. A 
gas tank is placed in the rear of the motor, and an oil 
tank under it. At a short distance from the trailing edge 
of the middle wing a seat for the rear gunner, with the 




The Ameriran-maile Caproni, equipped with three l.iherly motors 



40 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A Caproni hydroaeroplane equipped with three Fiat A. -1-2 motors rated at 300 h.p. eaeh. The Caproni Biplane has also been suc- 
cessfully used in naval work. For this purpose twin pontoons have been fitted to the lower plane, with suitable attaching braces. 



usual arrangement for machine guns and ammunition, is 
installed. From the height of the gunner's seat to the 
rear end the fuselages are linen covered. A Pensuti tail 
skid with shock absorber is at the end of each fuselage. 

Control Surfaces 

As on all Caproni bombing planes, the stabilizer, ele- 
vator, rudders and ailerons are of steel tubes. The tail 
surfaces are very ample, as can be observed from the di- 
mensions given. The stabilizer is solidly braced to the 
fuselage by means of cables and steel tube struts. It 
bears the three characteristic vertical rudders. The ailer- 
ons are six in number, one at each of the ends of the three 
wings. 

As also on the other Caproni bombers, dual control is 
fitted so that the plane can be controlled by either pilot at 
will. The control system for ailerons and elevator is a 
combination of the wheel and stick method; the vertical 
rudders are controlled by a foot bar of the usual type. 

For emergency use, the pilot on the left also operates 
a hand pump, sufficient to feed the three motors by pump- 
ing from the central tank. Each motor has its own oil 
tank and a small radiator for the cooling of the oil. 

The lateral motors have a nose radiator, fastened on 
the same beams forming the engine bed. The central mo- 
tor has two radiators, high, narrow and streamlined, each 
placed at the two rear interplane struts between the cen- 
ter wing sections, middle and upper plane. All the ra- 
diators are of the honeycomb type, and equipped with 
shutters. 



Lighting and Heating 

The lighting systems for navigation, signalling and 
landing, and the heating system for the crew are fed by 
a wind-driven generator of one kilowatt, combined with a 
large storage battery. 

Instruments 

The instruments are all set in a large dashboard in 
front of the pilots. Besides the usual standard instru- 
ments for navigation, motor and radiator control, each 
pilot has a Pensuti Air Speed Indicator. Some machines 
are also equipped with an Absolute Speed Indicator. 





CAP12ON1 



Left One of the two tail skids. The skid itself is of ash, 

wrapped with linen and shod with a metal shoe. 

Right- One of the two landing chassis units, composed of 

four wheels with double rims and double tires. 



MULTI-MOTORED . \KKori..\NKS 



II 



, \ 



pcll.-rs Hi'- hull has a (in ami two steps. This Up,- of boat was much used for patrol duly. 



Curtiss H-16-A Flying Boat 



Tin II -Mi A is :i t in-i-iiiiiin-d M-aplaiic with a flying- 
l>oat hull, usin^ trai-tor propellers. The pilot and ob- 
scner .-in- seated in a cockpit about half-way ln-twrrn the 
linw mil tin- winjjs. where they have an e\ei Hi lit view. 
The 11 li! is also fitted with a gunner's cockpit the same 
as tin IIS :. In addition, a wirrlrss opi-rator is rarricd 
"nside the hull just forward of the wings and hark of tin- 
pilots. Ali-ilt tin- winiis an additional nun ring is fitted 
COM rim; tin arc of tin- al'ovr and between tlie wings and 
tin- tail controls and to take care of the region to the rear- 
and l low tin- tail .-ontrols; gun mounts are also fitted. 
swinjiini: i\ brackets through side doors in the hull. The 
hoinh near is opi-ratrd from the forward gunner's eoekpit 
and four lioinli-. wi-n- rarrii-d. two under either wing. This 
typi- of boat proved very MTV in-able. 

General Dimensions 

Win? S))n I'pprr Plum- 98 ft. 6% in. 

^|>.in - l.owrr I'lnnr 68 ft. 11% in. 

Di-ptli ..f \V in); Chonl 84<%4 In. 

ti.-ip iM'twrrn XVinjr- Sfi^ili In. 

.. r Nun.- 

,,f Mm-hini- ovrrull 46 ft. l%o in. 

M.-i-lit of MarliiiH- overall 17 ft. 8% in. 

i- of Incidence 4 dejrrees 

Dihrilnil Anfflr 1 degree 

luu-k None 

\Vint' Curv R. A. F. No. 6 

lli.ri/.Mital -it.'iliilixer Anple of Incldenrr ... 2 degrees pos. 

Areas 

I'pper (without Ailrrons) 616.2 sq. ft. 

I.i wrr 4-13.1 sq. ft. 

.is 131 sq. ft. 

Horizontal -ital.iliwr 108 sq.ft. 

Vertical St il.iliier 31.1 sq. ft 

or- 58.4 sq. ft. 

Kudili r J7.9 sq. ft. 

nl* ?4 sq. ft. 

Totnl Sui)|H)rnii)f Surface 1.190J sq. ft. 



(welfrht carried per MJ. ft. of support- 8.S4 lb. 

in|r surfaci-) 

Londinir (per H. H. I'.) 15.42 Ihs. 

Weights 

Net Wei(rht Mnrhine Kinpty i;.'i:,i; ll.s. 

Cross Wright Mnrhine nn<l Ixid IO.I7J Ihs. 

fseful Ix>n<l :..'.>(! Ihs. 

Fuel and oil I^.T Ihs. 

Crew i Ihs. 

load . . 1.029 Ihs. 



Totnl :Wlfi Ihg. 

Performance 

Speed Minimum Horizontal Klipht 9.5 miles per hour 
Sprnl Minimum Horizontal Kli(rht j.i miles per hour 
Climhin)! S|M-1 I.OOO fret In 10 minutes 

Motors 

2 Liberty- 1-' cylinder. Vre. Four-Stroke Cycle Water cooled 

Horse I'nwer (rarh motor IMO) 660 

Weight per rated I lorsc I'ower 2,55 

Bore and Stroke 5x7 in. 

Furl Consumption pi-r birr (loth motors) 62.8 gals. 

Fuel Tank Capacity 300 gals. 

Oil Capacity Provided 10 gals. 

Fi-l Consumption per Brake Hnrsi- I'ower per 0.57 Ibs. 

Hour 

Oil Consumption per Brake Horse Power per 0.03 Ibs. 

Hour 

Propeller 

Material 

Diameter, according to requirements of performance. 

Pitch, according to requirements of performance. 

Maximum Range 
At economic speed, about 875 miles. 




42 



MILTI-MOTOKK1) .\KKOPI..\\KS 




I . I N 

from >' | In lin . hours. 
In iiml'.K-tiire. 



ng Bout, equipped uitli two Liberty inuturs. It ca n. and li.is a cruising railins of 

Throughout, I In- \arious p.irt re so designed that efficient priMluction methods ean ! used in its 



F-5-L Navy Flying Boat 



Tin- II I lying Moat is a twin-motored tractor bi- 
plane, ha \ing n total Hyinn weight nf lu-arly 7 tons, a 
cruising radius of ]iil._. hours as a tighter, or S 1 - hours 
as -i liiiiiilu-r. It carries a military load of over I KM) Ibs., 
with -i crew of four mm. It is so designed that it may 
l)r ijiiii-kly .-Hid efficiently built. 

Tin- I ' ." I is i somewhat larger machine than either 
the II-l-J or the H-l(i and is capable of carrying a greater 
useful load. 

I Mini urn iit.illy the plnnc is similar to our American 
Curtiss Hying bouts particularly the H-1G model. Hut 
in si/e .'11111 details it is quite different, being larger and 
better titled to emergency production. For example, with 
\eeptinns the fittings are soft sheet steel, cut from 
Hat patterns and bent to shape. 

This obviated the necessity of dies and drop forcings, 
which are particularly difficult to obtain under war condi- 
tions. The struts, likewise, are uniform sections, that is, 
not tapered, so that they can be shaped with a minimum 
of hand labor. Throughout, the parts are such that du- 
plication is easy, production methods possible, and read- 
ily available equipment suitable. 

The specifications herewith will give some idea of the 

si/, mil eapaeity of this seaplane. It will be noted that 

the lift per square foot of surface is from 9.3 to 9.") Ibs. 

,uare foot and is somewhat greater than land prac- 

The I-' -.1-1. is the latest development of the boat type 
seaplane, having the tail surfaces carried on the fuselage 
construction and the fuselage entering into the hull of 



the boat. The Curtis, boat seaplane may be i sidcrcd 

a forerunner of this type. The characteristics nre a fuse- 
lage similar to that of a land machine, planked in to form 
a boat body and having planes or steps similar to a hydro- 
plane at the forward end. 

Sl'l.c II If VI IciNS OK \.\VY F-5-L FLYING IK i \ I 

Overall upper wing (including ailerons) 103 ft. 9% In. 

Overall lower win* 7 ft. I in. 

Overall li-ii(rtli of lin.it 49 ft. 311,,, in. 

Overall heijflit of boat 1H ft. 91 4 ' in. 

\Vimr chonl (II-IJ curve) H ft. 

Cup iM-twren upper and lower panels C. I.. brams.H ft. 10% In. 

Antflr <>f incidence of wlnjrs plus 3 drg. 4<) mln. 

Dihedral of winjf 1 ' . d. ir 

Stagger of win);* Nnne 

Angle of incidence horizontal stab, plus iy t deg. 

F.ngine sect, panel 10H sq. ft. 

liili-nn. and upper outer panels (31 1 s<). ft. each) 611 sq. ft. 

A il.-nins (.',!) sq. ft. each) 11H q. ft. 

Sidewalks (: s<|. ft. each) 66 sq. ft. 

Ixiwer wings (.'Ml sq. ft. each) - 

Nun-skid planes ( l.i si|. ft. each) 3<l i 't. 

Horiwmt.il stahilij^-r 1 2\ - 'ft 

Vertical stal.iliwr 35 * ft 

Klevators (.* .sq. ft. each) 56 s. ft. 

Rudder 33 ft 

Total lift surfaces (including ailerons) 1.394 s ft. 

Mull length 45 ft. :t 

Hull width -ft. 

Hull height ft. 1 in. 

Pontoon length ft. 

Pontoon width "in. 

Pontoon height 35% to. 

Power plant .'I .ilx-rty Motors 

Pro|M-llers (subject to change), '-blade. . .10</, ft. fi", ft. pitch 




Hear view of the K-5-1. flying boat in flight. 



TEXTHOOK OF APPLIED AERONAUTIC ENGINEERING 



Streamline of Boat Noteworthy 

The most noticeable feature in the F-.i-L is the degree 
to which the hull or boat has been streamlined. The hull 
cover sweeps aft, broken only by the cockpit openings. 
From an aerodynamic standpoint this is more efficient than 
the construction of the H-16, where a raised cabin is used. 

On this model, as on the H-16, the fin edges are con- 
tinued aft and join into the lower longeron, giving a 
much stronger structure and better streamline form. An- 
other feature in the hull construction that is noteworthy 
is the use of veneer instead of linen doped and painted on 
the after hull sides. It was found in practice that the 
linen failed in heavy seas or on a bad landing, but this 
failure was obviated by the use of veneer. 

With few exceptions, all large seaplanes have been pre- 
viously built with unbalanced control surfaces. However, 
on the F-5-L both the ailerons and rudder are balanced. 
The purpose is, of course, to increase the controllability 
of the unit, and in the case of the aileron control the re- 
sult is as anticipated. 

Differing from the usual control surface balance con- 
struction, the balance on these ailerons is cambered so 
that it has a positive lift. By this construction the ailer- 
ons tend to be more sensitive in their action and to operate 
with less difficulty and with less balance surface. 

The planing action is increased by the use of vents ex- 
tending through the hull aft of the rear steps, similar to 
the vents that are used on the pontoons of the R-6 Cur- 
tiss model. It was stated that the hull swept aft in a 
perfect streamline, and the cabin top over the pilot's cock- 
pit was eliminated. However, a certain amount of pro- 
tection is afforded the pilot by small adjustable wind- 
shields. 

The whole layout of the machine is such that the du- 
ties of the crew may be most readily carried out. The 
observer's cockpit is in the nose of the machine and from 
it the widest range of vision is possible. At the bow is 
mounted the bomb sight and adjacent to it are the bomb 
release pulls, ammunition racks, signal pistols, binoculars, 
etc. A machine gun turret is mounted on the scarf-ring 
of the forward cockpit, so that the observer may aid in re- 
pelling aircraft attacks or, if necessary, sweep the deck 
of the submarine with machine gun fire. 

The pilot's cockpit is just aft the observer's cockpit, 
and may be readily reached from it when the machine is 
in flight. The pilots are seated on comfortable seats, 
hinged on a bulkhead and attached to a transverse tube 
by means of a snap catch that may be instantly released. 
This permits the observer to pass aft at will without dis- 
turbing the pilot. 

A wheel control of the dual type is used. It comprises 
a laminated ash yoke on which are mounted the two aileron 
wheels connected by an endless chain. An instrument 
board containing tachometers, altimeters, air speed indi- 
cator, oil pressure indicators, inclinometer, and pilot- 
directing bomb sight is mounted directly in front of the 
pilot. 

On the starboard side of the hull are the individual 
engine switches, ammeters and emergency switches, to- 



gether with the circuit breakers. The two compasses are 
mounted at some distance apart, so that they cannot inter- 
fere with each other. One is on the deck and the other 
on the fioor. All instruments are self-luminous, but in- 
strument hoard lights are provided. 

The spark controls are at the starboard side of the star- 
board pilot's seat, but the throttle controls are between 
the two pilots, so that either may operate them. Fire 
extinguishers are placed conveniently at each station, 
those in the pilot's cockpit being attached to the bulk- 
head beneath the seat. 

The wireless operator's station is on the starboard 
side just aft the pilots. The equipment is mounted on a 
small veneer table, and used in conjunction with a tele- 
scopic mast that is carried in the stern. A celluloid win- 
dow in the hull side provides necessary light. 

Mechanics Stationed Amidship 

The mechanics' station is amidships by the gasoline 
tanks and pumps, and their main duty is to see that the 
plane is " trimmed " by pumping gasoline from the tanks 
alternately ; to see that the engines do not overheat, and 
that all parts function properly. The water and oil 
thermometer are mounted on the sidewalk beam adjacent 
to the mechanics' station. 

Aft the mechanics' station, or wing section, is the rear 
gunner's cockpit. Three guns are accessible from this 
station, and it also provides a good point of observation 
or position for aerial photography. 

All machines are equipped with inter-communicating, 
telephones, the receivers being incorporated in the helmets 
and connection effected by terminal boxes at each station. 
It is thus possible for all members of the crew to be in 
constant communication. 

Voluminous Equipment Carried 

In addition to the equipment indicated, the following 
are some of the miscellaneous items usually carried: Tool 
kits, water buckets, range and running lights, pigeons, 
emergency rations, drinking water, medicine chest, sea 
anchor, chart board, mud anchor, anchor rope, heaving 
lines, signal lamp, binoculars, Verys pistol, ammunition, 
life jackets, and possibly electric warmers. Included 
also are the priming cans, drinking cups and usually sev- 
eral personal items. All this is exclusive of the ordnance 
equipment of bombs, machine guns, etc. 

Considering the size of the machine and the amount of 
material carried, the performance is quite remarkable. 
In fact, it compares very favorably with the performance 
of land planes having the same specifications and not 
hampered by the heavy boat construction. 

The time required to get the machine from the water 
varies with the wind velocity, but with a 15-mile wind 
and the plane fully loaded, from 30 to 40 sec. is required. 
The speed at take-off is about 47 knots on the air speed 
indicator, and a machine of this design has made a climb 
of 4200 ft. in 10 rain. 



28 . 




































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Design of the new four-motored 600 h.p. passenfter-carrying Sikorsky biplane. 




HANDLEY PAGE 

TWW LIBERTY MOTORED 

TYPE O100 BOMBER 



Scale cy /! 



46 



MULTI-MOTOR KI) AKRO1M.AXKS 




Tin- Twin-Libcrty-Motorcd American Handley-l'age. 



A machine of tins typr can be utilized fur lung distance mail, passenger and 
freight service. 



The Handley-Page Type 0-400 Bomber 

Hoth in Great Britain and in the United States, the General Dimensions 

H.-m.llev-l'agc h.-is heen the principal machine to be put S P". "PP" P lane 

, , , . rp. Span, lower plnne 70 ft. in. 

into <iu:mtity production fur bouMag purposes. The ( ',,,_ ,,,,, ],,,. lofi. ciin. 

American design is similar to the British, except that Lib- ^ap between |. Lines 1 1 ft. "in. 

erty " I-'" K)0 h.p. engines are employed in the former. Length over all 63ft. 10 in. 

and the Holls-Royce or Sunheam in the latter. Height over all at overhang cahane . In. 

A-" >i- * << one pilot and two or 

three gunner*, and an observer who operates the bomb- 
dropping devices. Their placing is ns follows: At the Areas 
forward end of the fuselage is the gunner who operates a Si/nor* 

ii.iir of flexible Lewis machine guns. Bowden cables at 

.... , , , , T, I pper plane with ailerons lOlH 

one side of the cockpit permit the release of bombs. Be- y^WJM (2) each Hi 

lun.l th< -gunner is the pilot's cockpit from which the gun- | x)Wer p | ane 630 

ner's cockpit is reached through an opening in the bulkhead Total wing area with ailerons 1648 

separating the two compartments. The pilot is seated at I'pper stabilizer 

th. right side of the cockpit. Beside him is the observer's {^*" to ^ ah ( "'j"' r ^0 

seat, hinged so it may be raised so as to permit access. j.. jn H 7 

Bomb-releasing controls are placed on the left side of the Rudders (3) 46 

observer extending to the forward gunner's compartment 

and running back to the bomb racks located in the fuselage Weights, General Pound , 

just between the wings. Machine empty 1466* 

Forward compartments are reached via a triangular FueJ am j () j| 3496 

door on the under side of the fuselage. Bomhs So* 

Aft of the bomb rack compartment, the rear gunners Military I-oad . 

are placed. Two guns are located at the top of the fusel- **?*, ' 1 1 ; ; '. ; \ ] \ \ \ \ \ \ \ ] \ \ \ \ \ [ \ [ \ \ \ \ \ * M 

age and a third is arranged to fire through an opening in Weignt per h orM . pawn 175 

the under side of the fuselage. One gunner may have 

charge of all the rear guns, although usually two gunners Summation of Weights 

man them. A platform is situated half way between upper Power Plant . . . 

and lower longerons of the fuselage, upon which the gun- fjjjj^ am j 'n,,^,,,,,^' ^uip^nt '^i '.! ! ! i!" !! 610 

ner stands when operating the upper guns. Armament 3* 

Machines of this type can be utilized for commercial Bombing equipment 3000 

aerial transportation, and are capable of carrying loads Body structure . 

which would enable them to efficiently perform this func- Tall ""^^^ '"' ^^^ 

tion. By leaving off the various military fixtures, the use- ch j) u 710 

fill carrying capacity, for passengers or freight, will be 

greatly increased. Total 



48 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



WEIGHT SCHEDULE 
Power Plant 

Engin.e complete with carburetor and ignition system 

J x 835 = 

Radiator 2 x 112 = 

Hadiators and engine water -2 x 150 = 

Fuel tank empty and pipes 

Oil tank empty and pipes 16x2= 

Exhaust manifolds -2 x 7.5 = 

Propeller and propeller hubs 3 \ GO = 

Cowling -2 x 100 = 



rounds 

1688 
994 
300 
350 
32 
150 
190 
200 



Volumes 

Bomb section, 3 ft. 5% in. x 5 ft. 2 15/16 in.x4 ft. 5 in. 
Hear gunner's platform (upper) 3 ft. 3'/ 8 in. x 5 ft. 

1% in. x 4 ft. -"/, in 

Hear gunner's platform (lower) 2 ft. 4. in. x 5 ft. 
1% in. x 4 ft. ->'/, in 



Cu. Ft. 
80.6 

71.45 
54.2 



Total volume 200.25 



Total 



Height 
(Feet) 
. 

5,000 . 

7,000 



Performances 

Speed Time of Climb 

(M.l'.ll.) (Minutes) 

. . . 92 

. . . 90 12 

18 



Fuel and Oil 10,000 85 32 

Fuel (280 gallons) 2280 

Oil (2x 15.3 gallons 2x 108 ll,s.) =J18 

Planes are not swept back and have no stagger nor 

Total -196 decalage. Beyond the engine nacelles, both upper and 

Passengers and Equipment l wer P lanes have a dihedral angle of 4 degrees. 

Pilot and clothing 170 ^'ing section employed, R. A. F. No. 6. Angle of lower 

Gunners and clothing 340 wing chord to propeller axis, 3 degrees. 

Dashboard instruments, fire extinguisher, tools and Aspect ratio of upper wing, 10; lower wing, 7. 

ma P s Planes are in nine sections. Upper plane center section 

Total gjO 16 ft. in. wide. Intermediate sections 22 ft. in. wide; 

overhang sections 16 ft. 10 in. wide. Beyond this, the 

Armament ailerons project for a distance of 3 ft. 2 in. 

Two forward machine guns, mounting and ejection am- Lower , ne jn four sections . two between fuselage and 

munition and sights 12X) 

Three rear machine guns, mounting and ejection am- en g' ne nacelles and two outer sections. 

munition and sights 180 Interplane struts spaced as follows : nacelle struts 8 ft. 

in. from center of body; intermediate struts 10 ft. in. 

Total from nacelle struts ; outer struts 1 2 ft. in. from inter- 
Bombing Equipment mediate struts. Overhang rods anchored 14 ft. in. from 

Bombs 2500 outer struts. Overhang beyond bracing 6 ft. in., includ- 

Bomb releases and sights 500 j n g ailerons. 

Ailerons are 20 ft. 7% i n - 5 n ; 3 ft. 9 in. in chord. 

i otal oOOO 

Overhang portion 3 ft. lyj in. wide. 

Body The accompanying drawing illustrates the manner in 

Body frame 953 + 97 = whieh the main planes are hinged aft o f the eng j ne n a- 

Front control' and rear control' !!!!!! i!/!! !'" !!!!"!! 100 celles ' Permitting the wings to be folded back so as to fa- 

cilitate housing in a comparatively narrow hangar. In 

Total 1210 folded position the measurement from leading edge of 

Tail Surfaces with Bracing wi ? * centerl ' ne of fusela g e is 15 ft - 6 in - 

,_ For bracing between planes, oval section steel rods are 

Stabilizers (no covering) 3 57.2 

Elevators (no covering) 4 34.4 used exclusively. Jinds are formed to a solid section 

Fin (no covering) 1 6.4 which is threaded and fitted with a trunnion barrel and 

Rudder (no covering) 2 28.8 forked terminals. 

Covering 35.4 _ . 

Struts and wires , 24.4 

The fuselage is built up with the usual longerons and 

Total 187. cross members. Bracing is with solid wires with swaged 

Wing Structure or forked ends ' 

Upper wing with fittings, aileron and fuel tank in center Total len g th of fuselage, 62 ft. 10% in.; maximum 

section; lower wing with fittings 2032 width at tile wings, 4 ft. 9 in., tapering in straight lines to 

Interplane struts 235.5 2 ft. 11 in. wide at the stern ; maximum height, 6 ft. 10 in. 

Interplane cables ... 261 j n fl ving position the top longerons are horizontal to the 

Nacelle supports 2 x 105 = 210 " ,, , , ,. . 

propeller axes; top longerons 12 ft. 3 in. above ground. 

Xotal 2738.5 Leading edge of planes 1 2 ft. 2 in. aft of fuselage nose. 

Chassis Tail Group 

Wheels complete, 2 x 170 = 340 The tail is of the biplane type with a gap of 6 ft. in. 

Shock absorber, 4 Average chord, 8 ft. 6 17/32 in. Chord, above bodv, 5 ft. 

Miscellaneous parts, 4 x 30 == 120 _ ,' ' 

Tail skid 50 ln ' ^pan f stabilizers, 16 ft. 7y-> in. 

There are two pairs of elevators 1 ft. 10 15/32 in. wide 

Total 710 and 8 ft. 5 J X> in. long. 






MII.TI-.MOTOKKI) AKKOIM..XM- - 



M 




The iiu; rim-triirtion of tin- lliiinllc\-l'.ij:e machine-. 



Struts fruiii hotly to top t.-iil plane spaced 2 ft. !' t in. 
from renter to center. From these, tlir outrr forward 
struts and rudders are spaced i> ft. :>' in. 

Central M rtical tin, I ft. () in. wide. 

Rudders are balanced. Width t ft. HI' -in. Control 
failles run to their tr.-iilini; > ili:< >. and a MBpeBMtfag 
cable runs through the fin from the leading edge of one 
rudder to the Icadiiii: cdae of the other. 

Landing Gear 

The landing gear comprises four 2 ft. 11 7/16 in. dinm- 
cter wheels with tires 7^ j,, wide. Wheels arranged in 
tun |i i;r- < :ieh pair h.-iving a 4 ft. 6 in. tread, and inner 
wheels spaced 5 ft. Sfo in. from center to center. 

.\\le-, -in Imiu" il at center. Vertical shock absorber 
iiiecli.-inisiii enclosed in /in aluminum casing. 

Tail skid is the usual swivelled pylon-mounted ash skid, 
shod with a sheet steel plate. 

Engines 

Tin- Liberty engines are entirely enclosed in streamlined 
sheet aluminum nacelles between the planes. Propeller 
axes 10 ft. Ill 16 in. above ground when machine is in 

Hying position. 



MANDLEY-PAGE 




((Mr Hi' till' four shock ;lli 

sorlx-r units nf the IUmll<-\ 
Pafrr ItmulH-r. The stream- 
line sliet-t .iliniiimiMi en-iriu' 
is rrmoxetl til sliow the nirth 
IM) nf -trin^illj.' the rlasti<' 
cnril tH-twt ell v.nlilles llttlicheil 
tn tin- I i \i-il linicr MI ii I the 
.slidini.' rinls res|iecti\fl\. 



Propellers 10 ft. 6 in. diameter. Imth revolving in the 
same direction. 

Kadiator faces have adju.stnhle shutters to regulate tin- 
air admittance. Water capacity of radiators, ,S(M) Ibs. 

Each of the two Liberty " 1-J " engines gives -KM) h.p. 
at 1.625 r p.m. More and stroke 5x~ inches. I in I ton 
sumption, ..95 Ibs. per h.p. hour; oil, .03 Ibs. per h.p. hour. 
Engine weight, M, (Ht Ibs. with propeller. 

Tanks located above bomb compartment. Fuel capac- 
ity, 280 gallons; oil, 15.3 gallons. 




Thr transatlantic type. British make. Handle) -Pap- biplane, powered with four Rolls-Kojcc motors 



50 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The J. V. Martin Cruising Bomber. One of the very original machines developed in this country by Captain James V. 
Martin for the U. S. Army. Two Liberty "1-3" engines, located within the fuselage, drive two four-bladed tractor screws 
by means of bevel gears. This machine has the Martin automatic wing-end ailerons, K-bar interplane struts and other un- 
usual mechanical constructional features. 

The Martin Cruising Bomber 



The Martin Cruising Bomber is equipped with two en- 
gines located in the fuselage and driving two tractor pro- 
pellers by means of bevel gear transmission. Since either 
engine will drive both propellers, the failure of one of 
the engines does not impair the efficiency of the plane. 

Either two Sunbeam 300 h.p will drive the plane at 
74 m.p.h., or two Liberty 400 h.p. engines will drive 
plane at 81 m.p.h.; in either case with a two ton useful 
load. 

Fully loaded the machine can make a.speed of 110 miles 
an hour. The useful load is three tons not including one 
ton of fuel and oil. 

The K-bar cellule truss is used, which eliminates half 
of the cellule structural resistance due to wires transverse 
to the line of flight. 

The machine is also provided with the Martin retract- 
able landing chassis, which has been found to be strong, 
light and reliable. It eliminates 14 per cent of the struc- 
tural resistance of the Bomber. 

Mr. Martin claims that safety and dependability are 
increased because of independent transmission support, 



for the propeller breakage will not endanger cellule truss, 
and because cellule stresses are low and are more ac- 
curately calculable. 

As the engines are enclosed, resistance is no greater 
than where a single engine is used. Such placing makes 
the engines accessible for minor repairs and adjustments. 




View of the power plant of the J. V. Martin Cruising Bomber. 




A view of the Martin Blue Bird in 
flight. This small machine has the K-bar 
truss and retractable landing gear, as does 
the Martin Bomber described above. 



Mn/n-MOTOHKI) AKKOl'I.AM.S 



51 




Tin 



Martin Twin l.ilx-rtv Motored Bomber. 



Glenn L. Martin Bomber 



The Martin bomber is a machine of excellent perform- 
ance, as show n in its official trials. An official high speed 
at the ground of 11H.."> m.p.li. was made on the first trials, 
with t ill bomhiin: load on l>oard. This speed lias been 
bettered since, due to the l>etter propeller efficiency arrived 
at by e\pi-nsj\e experiments. With full bomb load, the 
cliinhinir time to III.OIMI ft. was I ,"i niin.. and a service 
ccilini: of between lii.oiin and I7.OIM1 ft. was attained. 

As i militarv in.-ieliiiie. the Martin Twin is built to ful- 
fill tin rci|uircnicnts of the four following classes: (1) 
night bomber: (2) day bomber; (3) long distance photog- 
raphy; ( 1) gun machine. 

\- i night bomber it is armed with three flexible 
I w is machine guns, one mounted on the front turret, one 
on the re.-ir turret, and the third inside the body, and firing 
to the rear, liclow and to the sides, under the concave 
lower surface of the body. It carries l.'.(M) pounds of 
bombs and looo rounds of ammunition. A radio tele- 
phone s, t and the necessary instruments are carried on all 
four types. The fuel capacity in all four types is suffi- 
cient for one-half hour full power at the ground and six 
hours' full power at 1 .1,000 feet, and enough more for 
about six hundred miles. 

As a day bomber two more Lewis guns are carried, 
one more on each turret. The bomb capacity is cut to 
!bs. to give the higher ceiling necessary for day- 
work. 

(3) When equipped as a photography machine, the 
same number of guns as in the case of the day bomber are 
carried ; but in plaee of the bombs two cameras are 
mounted in the rear gunner's cockpit. One camera is a 
short focal length semi-automatic, and the other is a long 
focal length hand-operated type. 

The gun machine is equipped for the purpose of 
breaking up enemy formations. In addition to the five 
machine guns and their ammunition as carried on the 
photographic machine, a semi-flexible 37 mm. cannon is 
mounted in the front gun cockpit, firing forward, and with 
m fairly wide range in elevation and azimuth. This can- 



non fires either shell or shot, and is a formidable weapon. 
The Martin Twin is easily adaptable to tin- commercial 
uses that are now practical. They are: (1) mail and 
express carrying; ( ' ) transportation of passengers; ( :( ) 
aerial map and .survey work. 

(1) As a mail or express machine, a ton may be carried 
with comfort not only because of the ability of the machine 
to efficiently handle the load, but because generous bulk 
stowage room is available. 

(2) Twelve passengers, ill addition to the pilot and 
mechanic, can be carried for non-stop runs up to six hun- 
dred miles. 

(S) The photographic machine, as developed for war 
purposes, is at once adaptab.< to the aerial mapping of 
what will become the main flying routes throughout the 

General Dimensions and Data 

1. Power Plant 

Two l.'-cyl. Liberty engines. 

i. Wing nml Control Surface Areas. 

Main planes (total) 1070 sq. ft 

I'pper planes (including ailerons 450 

I.ower planes (including ailerons ) '>'<> 

Ailerons (each) MJ 

No. of ailrrnns * 

Vertical Fins (each) 8.8 

No. of fins i 

Stabiliwr 

Hewitor M .''' 

Rudders (each) 16,50 

Vo. of rudders 

3. Overall Dimensions 

Span, upper and lower 71ft. 5 In. 

Chord, upper and lower 1 " 10 " 

Gap " " 

Length overall * " 

Height overall 14 " 7 " 

Incidence of wings with propeller axis 

Dihedral None 

Sweep back None 

Deealage (wings) None 

Stabiliser, setting with wing chord 

adjustable between ** 

normal letting 9 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



country. The accuracy that is being obtained in aerial 
photography should be of vast value in surveying and 
topographical map work. 

Wing Structure 

The wing truss is conventional outside of each of the 
engines. From one engine through the body to the other 
engine, the truss system is a very rigid but light one of 
streamlined steel tube tension and compression members. 
These members are arranged primarily with three objects 
in view, that is: (1) Ease of removal of the engines. 

(2) Rigidity throughout the landing and power system. 

(3) Simplicity and hence low weight and resistance. 
The wing spars are of the conventional spruce eye- 
beam type. Interplane wood struts are two-part and 
hollow, and they are pin connected to the wing fittings. 
The wing ribs are of a novel type, developed through very 
extensive experiments on all types. They weigh, each, 
eleven ounces and have a minimum factor of safety of 
eight. Scrap spruce is employed in their manufacture, 
and by the use of a clever jig, speed and accuracy in their 
assembly make it a fine production job. 

The wing fittings completely surround the beam in every 
case, and are designed from every minute consideration to 
give a factor of safety in excess of six. Double flying 
cables and single landing and incidence cables are used 
throughout. No turnbuckles are employed. A right and 
a left-hand threaded eye-bolt made into the cable by the 
conventional warp method, engage similarly threaded 
clevises, pinned to the fitting ears. Streamline wires are 
interchangeable with the cables in this system. 

Swaged tie rods are used throughout for the internal 
wing bracing. Pin joint connections tie the lower wings 
to the body, and are also used at all panel connections. 

A minimum factor of safety of six is secured throughout 
the wing truss for the heaviest loaded conditions. 

The body in many respects is the most interesting part 
of the airplane. At the nose is the cockpit for the front 
gunner, mounting at its edge the scarfed gun mount. The 
front gunner has access to a passageway through which he 
can go aft to handle the rear lower gun, or sit beside the 
pilot on a folding seat. The pilot is placed on the right- 
hand side of the body and well up so that his range of 
vision is the best possible. 

He is provided with a wheel type control and has a 



splendid view of the instrument board. At his right and 
under his seat is the hand wheel which operates the adjust- 
able stabilizer. Behind the pilot are the three main gaso- 
line tanks. 

The passageway and firing platform for the rear lower 
gun terminates at the rear wing beam station. Here, on a 
special mount, is the lower gun, which commands a large 
field of fire horizontally to the rear, below, and to both 
sides. This gun is operated from a prone position by 
either the front gunner, rear gunner, or a third man, if 
four are carried. 

The tunneling of the bottom of the body to permit the 
mounting of the lower gun has introduced difficulties in 
trussing which have satisfactorily been solved in a simple 
and light manner. The lower transverse strut and cross 
of transverse bracing wires usually found at each trans- 
verse section in the truss type body are replaced by two 
steel tubing struts. 

The ends of these struts are threaded right and left- 
handed, and engage similarly threaded forked ends which 
pin to the body fittings. By this means the transverse 
sections are squared up. 

In all other features the body is a combination of two 
standard types : the wire and strut truss, and the veneer 
plated wood truss. Three-ply birch or mahogany veneer 
is used on the body sides, at the nose and tail, and in the 
bulkheads employed in the body. Swaged tie rods and 
threaded clevises are employed throughout for truss ten- 
sion members. The longerons aft of the rear wing beam 
station are hollowed out between fitting attachment points, 
the degree of routing increasing with the progress to the 
rear. A cheap, simple and effective steel plate longeron 
fitting is employed at the rear body panel points, while 
heat-treated chrome vanadium fittings are found at the 
main wing truss attachment points. 

The tail skid is braced entirely by the internal body 
structure at this point. It is universally pivoted and is 
sprung by sturdy elastic chords inside the body to receive 
the landing shock. 

Engine Units 

The Liberty engine is firmly mounted in a light girder 
box of veneer, resting on brackets on the four main wing 
struts. It is so secured that engine, radiator, airscrew 
and nacelle may be removed intact from the wing struc- 




1 One of the four landing wheels showing the streamline shock absorber casing and the wheel guard to protect the 
propeller from stones and mud. -2 One of the main ribs, showing sections through wing beam and leading edge. 3 Fit- 
ting at ends of wing struts. 4 Tail skid unit, with shock-absorber elastic removed. 



MlLTI-MOTOHKl) .\KHO1M..\N I - 



turr. A nose radiator nf tubular i-i-ll construction, weigh- 
ing Complete ^ ll>-.. is mounted in a unii|uc and \rr\ 
satisfactory iiiainn r. Two ll.iiii;. .1 steel rinys are In Id 
together h\ machine screws, .mil when in plan- wedge a 
strip of rnlilx-r firmly between (lu-in and tin laces .if the 
rirculiir Imlr cut in tin- radiator tor tin airscrew shaft. 
Thr rear ring carries platrs. which in turn liolt to plate-, 
secured .-it the cnil of the engine hearers. The whole 
weight of tin- radiator then is carried from its central 
hole. \o |nrt of the- nd:.itor touches am part of the 
mounting hut has a cushion of rul>l>er si paratmg it from 
the mounting and absorbing the- shock Iroiu the engine. 
I ich radiator is ei|iiippeil with shutters, operated nt tin- 
will of the pilot, for the purpose of regulating the water 
temperature. An expansion tank is let in to the trading 
portion of the upper wing above each radiator, and is 
connected to it. The top of (he engine is .\poscd. This 
aids iii cooling, of course; makes the engine more acces- 
sible for working o\i r. and permits the n diictioii of cowl- 
ing weight to minimum consistent with low head resistance. 

The airscrew used is the Douglas type, and is 9 ft. 8 in. 
diameter and li ft. 1 ill. face pitch. It is the best over- 
all hlade git ing a satisfactory high speed and climb at 
reasonable rev olutions. 

The three controls from each engine, carburetor, igni- 
tion and altitude arc positive controls, operated easily and 
convcnicnth bv the pilot, either in pairs or singly. 

An ample supply of oil is carried in a tank situated in 
each motor nacelle. 

Undercarriage 

The undercarriage is composed of four 800 by ISO mm. 
wheels. Four sets of triangulated struts carry the load 
from the two axles to the four main structural points of 
the machine. The axles are hung on the usual rubber 
cord suspension, but have a large amount of freedom not 
only vertically, but in the other two directions. All the 
lateral forces are taken up at the center trussing under the 
body. The two outside sets of struts are free to swing 
laterally, and hence only absorb the vertical component 
of the landing shock. Simplicity with extreme low weight 
and head resistance has in this manner I ecu secured but 
at no expense to the proper functioning and wear and tear 
n sistance of the gear. The flexibility of this arrangement 
absorbs all kinds of shocks in a very satisfactory manner. 

Controls and Control Surfaces 

A single wheel and foot -bar control is provided in the 
pilot's cockpit. The interesting point about the wheel 
control is that the usual weaknesses of this tyj)e have been 
eliminated. The aileron rabies pass over no drums, nor 
they hidden within tubes where wear can be detected. 
The dangers of the chain and sprocket aileron control, 
with its e\er present tendency to jam, are not encountered 
in this type. 

The IS in. wheel is keyed to a steel shaft which carries 
on it, within the upper gear case, an alloy steel bevel gear. 
This meshes with another gear keyed to a vertical torque 
tulic. running in ball-bearings mounted inside the control 
column. At the lower end, the tori|iie shaft carries a 
pinion which engages with a steel rack. The rack i 
guided inside the lower gear case, and has attached to it 



the dual aileron control cal h s. The whole unit is v.rv 
strong, rigid ami reasonably light. 1'ropcr power on tin- 
lateral controls is readily obtained, which in the (Base of 
either of the other types would m\ol\e ditiiciiltu s. 

e.|iial ami unbalanced nilerons are carried. These 
supplv the ncci ss-inh ln-li .1. -n . .>f lateral controllability 
required of ,-i machine of this t v pi 

The tail siirfans ,r. of steel and wood const ruction. 
It is noteworthy that the stabili/.er is adjustable from the 
I'll I hi , niir. tail surface structure is hinged at 

the rear stabilizer spar. The front truss system termi- 
nates in a \ertical tube, mounted in hi arings inside tin- 
body and threaded to engage a nut. Tables wound on a 
drum operated by the hand wheel at the pilot's side turn 
the nut and thus raise or lower the front of the stabiliser, 
and with it the tail surface trussing. A range in angle .>! 
the stabilizer of plus or minus three degrees from neutral 
gives the pilot n powerful means of halnncing the airplane 
in any flying attitude or for any load distribution. 

The ihvatiir is one piece, and, with its generous area 
and ease of operation, forms a positive control to be relied 
on in any emergency. 

Two balanced rudders, working in synchronism, permit 
the pilot to control his direction under any conditions with 
ease. In fact, when flying with one engine dead, the 
amount of rudder movement necessary to correct the off- 
setting force of the other engine is surprisingly small. It 
leaves an ample margin of control for maii.eim ring under 
these conditions. 

Gasoline System 

The gasoline system has been developed to eliminate 
the many troubles usually encountered from this vital part 
of the airplane. Three sturdy tanks, mounted securely 
inside the body, contain the main supply of gasoline. Two 
gravity tanks, mounted in the upper wing one over each 
engine, each hold gasoline enough for one-half hour's 
flight. All tanks are made from tinned steel. They are 
braced securely by many internal bulkheads, all scams are 
double lap. rolled and sweated, and all rivets used arc 
large headed tinned rop|>cr rivets. None of the tanks are 
subjected to any pressure when the system is in operation. 

The three main gasoline tanks drain into a combination 
distributing valve and sump operated from the pilot's com- 
partment. Any tank can be rut in or out of the line at 
will. 

I'ipes from the sump lead the gas to the two air-driven 
gear pumps located In-low the body. Valves, controlled 
by the pilot from his seat, arc provided in the pump lines. 
Hy means of these valves either pump may be by-passed 
on itself or allowed to feed gasoline to the carburetors. 
One pump alone is more than sufficient to feed both motors 
full on. Two are provided as a safety means. 

Leads from the pumps run out to the carburetors of 
both engines. A lead running from each of these main 
supply lines to the gravity tanks supplies them with gaso- 
line and serves to carry off the excess gasoline pumped by 
the main pump. An overflow pipi is led from each gravitv 
tank to the main tanks. 

A hand operated plunger pump is installed, and may 
be used to fill the gravity tanks or to supply the engines 
should I oth air-driven pumps fail. 




IO 




5UNDSTEDT-HANNEVIO 

TWIN MOTOBtD 

SEAPLANE 



54 



MII/n-MOTOKKI) AKKOPLANKS 




The Sumlste.lt-H.mniM..- Seaplane equipped with two Moilrl "I I" 1 1 ,II-S. ,.tt Kn|(inev 
(lluilt l>\ tin- \\itteiii.iim I.rwis Airri -.<-.) 

The Sundstedt-Hannevig Seaplane 



Tin- Stffidatodt-Hannevig seaplane lias In en d, signed for 
tin specific purpose of long distance tlvinir over the sea. 
In genrrnl. it lias been designed with an extra heavy sub- 
stantial eiinstriietinn. partieularlv on those parts subjected 
to tin- iircatcst amount of strain during flight and at land- 
ings. Midi as pontoon-.. HJII^S. and the entire rigging. 

In tin desiiiti. liowi-vi-r. only proved aerodynamienl prin- 
ciples have been embodied, assuring a positively efficient 
maeliine. and ("apt. Sundstedt lias made a large number of 
inipro\enients in structural details, affording the utmost 
.strength anil lightness of construetion. 

Tin seaplane is equipped for two pilots and two pas- 
's in the cabin of the fuselage. 



General Dimensions 



in. 
6 in. 
in. 
in. 

.' in. 

6 in. 

7 in. 



plane ............................... 100 ft. 

nwer plane ................................ 71 ft. 

Imril. lower pl.nie ......................... 8 ft. 

luinl, upper plane ........................ 8 ft. 

'"tween w iiip. ............................. 8 ft. 

'i nf i.nieliine over all ...................... 50 ft. 

Height of in n dine 'over all ...................... 17 ft. 

Dilinlr.il nnirle. lower plane .............................. 2* 

urvc .................................. f. S. A. No. 5 

n'timr surfHee ............................. 1,537 sq. ft. 

Ku.lil.-r area ....................................... sq. ft. 

T area ...................................... 44 sq. ft. 

\\YitrM ........................................... 10,000 Ihs. 

I n.iili'iir |HT h.p ....................................... 33 Ihs. 

l.iwilinir per sq. ft ...................................... 6 Ibs. 

estimated, full load .......................... 80 m.p.h. 

('liinliiiifr s|>citl, estimated ................. 3,000 ft. in 10 min. 

total ........................................ +40 



Pontoons 

Tin pontoons are of special Sundstedt design, embody- 
ing the highest developed features of streamline and fol- 
low tin most accepted construction practice. They are 
in pi' of Capt. A. P. Lundin's special three-ply Balsa 
wood veneer, covered with linen, and are each divided into 
eight watertight compartments, painted and varnished 



with torpedo gray enamel. They are 32 ft. in. long, 
spaced 16 ft. () in. apart from centers, and are light in 
weight, being 400 pounds apiece, including fittings. 

Each pontoon is equipped with an emergeiiey food locker 
accessible from the deck by means of a handhole. 

The pontoons are braced to the fuselage and wings by 
a series of steel tubing struts with Halsa wood streamline 
fairing. These tubes are of large diameter and tit into 
sockets mounted on the pontoons and wing spars. The 
entire assembly is amply braced by steel cables and tub- 
ing connecting struts. 

Fuselage 

The fuselage is of streamline design, and is flat .siiled 
in order to provide sufficient vertical surface necessary for 
good directional stability. It has a curved streamline 
bottom and hood running fore and aft. The construction 
is of white ash and spruce, consisting of four longerons 
and ash and spruce compression struts fastened thereto 
with light universal steel fittings, to which are also fast- 
ened and connected diagonally the solid steel brace wires 
and turnbuckles. 

The front end of the fuselage is fitted up much after 
the style of a closed motor car, with comfortable up- 
holstered seats for the pilots and passengers. This cabin 
is accessible by a door on each side at the rear end of the 
cabin. A very complete field of vision is obtained through 
a series of glass windows around the front of the pilots' 
seats, forming a recess in the upper deck forward of the 
windows. 

Directly behind this cabin, and balancing with the cen- 
ter of pressure is the main gasoline tank, with a capacity 
of 750 gallons, sufficient for 22 hours of full speed flying, 
and to the rearward of this is the adjustable open truss- 
ing, with a detachable hood and covering for access and 
inspection. 

The forward section is covered with a thin three-ply 
mahogany veneer up to the rear of the cabin doors, and 



56 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Sundstedt Aerial Cruiser being assembled. It is equipped with two Hall-Scott motors. 



aft of these, it is covered with linen, doped, painted and 
varnished. 

Control 

The control system operates on the standard wheel and 
rudder bar method, and is of special Sundstedt design, 
whereby all cables are located beneath the floor, leaving a 
clean control column and rudder bar without any wires 
in the way of the passengers or pilots. Dual control is 
fitted, side by side, directly connected, so that the ma- 
chine can be controlled by either pilot at will. 

All engine controls and switches are located on the 
dashboard, operative from both seats. 

Instruments 

A substantial dashboard is fitted in front of the pilots' 
seats in a plainly visible position, and is equipped with 
tachometers for both motors, clock, altimeter, speedometer, 
radiator thermometers, oil pressure gauges, shut off valves, 
ignition switches, and so forth, which are located within 
easy reach of the pilot. 

Power Equipment 

The power plant consists of two Hall-Scott Model 
" L-6 " h.p. engines, directly connected to two bladed 
pusher propellers. Each is mounted on a specially con- 
structed bed by the Vee method of interplane struts, with 
the engine beds, housings, and radiators all securely braced 
to the wings, pontoons and fuselage. 

The engines are supplied with gasoline by turbine driven 
Miller gasoline pumps which maintain a pressure of 3 
Ibs. in a special reservoir of the pump itself, under auto- 
matic adjustment, and eliminating all of the difficulties 
and dangers of the gravity and pressure feed systems. 
These pumps are regulated from the cabin and within easy 
reach of the pilots. 

Wings 

The wings are built up of five sections in the top plane 
and three in the lower. The center section of both the 



upper and lower planes are 18 ft. 10 in. long, and so de- 
signed that the pontoons, the power plant, and the fuse- 
lage can all be assembled completely before adding the 
remaining outer wing sections, thereby taking up a mini- 
mum amount of space in assembly during manufacture. 

The main spars are of laminated built up section, serv- 
ing to give a very high strength and exceptionally light 
construction of a combined I-beam and a box beam section. 

The upper wing has a chord of 10 ft. in. at near 
the junction to the center section, and narrows down to 
8 ft. 6 in. at the inside of the aileron cutout. Of this, 8 
ft. in. is well constructed web form of rib, while beyond 
this distance the cap-strips are run out with a small piece 
of spruce between, serving as a very flexible trailing edge, 
greatly increasing the stability and gliding efficiency of 
the machine. 




The underside of fuselage showing control connections on 
the Sundstedt-Hannevig Seaplane. It is covered by an alumi- 
num cowling. 



MII.TI MOTOKKI) .\KltoiM..\\KS 







other strains on the wings, and subjecting the wing ribs 
to the one purpose of lift only. 

The wing seetion used in the I'. S. A. No. .'>, whieli is 
especially designed f or |,J K |, S J M .,.,I nm j Kn . at | if , Sl . rv j ng 
as a medium between a scout and an extra heavy lifting 
wing, and, as well, lias high structural safety factors. 

The iiiterplane struts are nil made of seamless steel 
round tubing, streamlined with Halsa wood encased in 
linen, and the struts with reinforced ends are fitted into 
sockets which are bolted to the main spars of the wings 
l>y tour nicklc steel bolts straddling the wing spar to tie 
plates on the opposite side of the spar. 



The lower plain- is entirely constructed of solid rilis. 
with a chord of S ft. () in. The wing ribs are cut out of 
a spe.-ial thro ply x. n< , r. with lipped end-., ti t ting closely 
into the boxes of the I-beams, and fastened in place bv 
means of two cap straps, glued, nailed and screwed to 
the webs and wing spars. 

At the points of fastening the iiiterplane struts to the 
main spars of the wind's, there is an internal steel com 
pression tube, reinforced at the ends, bolted in place, and 
.socket, fastened directly to the main spars, mtcrhraccd 
diagonally with solid steel wires fitted with turnbuckles 
for adjustment and locked, taking up all of the drift and 







** i | 




Thr Kennedy " Ciant " Xeroplnne, equipped with I S.ilmsmi eriirfiies of .W h.p. each. Span. U.' ft.: length, HO ft.; height, 
in.; chord. II) ft.; gap. IO ft.; total weight, Ifl.lKK) ll.s. empty. Ttiis mnrhinr was ahamlonrcl in 1!U7, hut th- results !,- 



iniil with it h-ne l.e.-n put t,i use i,, huilding n not her Inrirr machine. This Inttrr nrroplnnc has a span of 100 ft.; length, 44 
hei-ht. .'. ft ; estimated speed. 130-130 m.p.h.; estimated useful load. 6400 Ib*. in additinn to erew and fuel necessary for 
i .VHP inHe flight. 








\l 



BURGESS 

TWIN - MOTORED 

SEAPLANE 



SCALL of FEtT 



McUughlin 



58 



Mri/n-MOTOKKI) AKHOIM.ANKS 



Burgess Twin-Motored Hydroaeroplane 



Tliis machine, besides being equipped with tin- usual 
complement of instruments, has the Sperrv gvroscopic 
stabilizer anil other impro\cd installations. 

General Dimensions 

Span, upper plain- 7 .' f t. in. 

Span, lower plane 51 ft. !l in. 

Chord, Ixith planes 7 ft. 7 in. 

Cap iM-tween planes 6 ft. 11 in. 

Ix-nplli over all :<-' ft. 5 in. 

II, ..-hi over all IS ft. * in. 

Cross writ-lit 5,380 II. s. 

Motors (.') Sturdevant 5A, rnch 140 h.p. 

( Hiding anple 8 1 /, to 1 

Climl> in in minutes 3^00 feet 

Spenl Miiirc, loaded 78-45 m.p.h. 

Planes 

I'pper pl.-ine is in .', sections the flat center section 
12 ft. (i in. wide; the outer sections each Hi ft. 8 in. wide; 
and the overhanging sections 1 1 ft. -I- in. wide. The ends 
of the ailerons project beyond the wing tips at either 
side for a distance of 1 ft. 6 in. 

Ailerons on the upper plane arc 12 ft. 10 in. in length, 
minimum with 2 ft. 1 in., maximum width 3 ft. 5 in. A 
small balancing portion beyond the wiring tips extends 
forward of the rear main wing beam. Control arms are 
located 7 ft. in. from the inner end of aileron. 

With the exception of the center sections, the planes are 
swept back at an angle of 3 degrees. On the lower plane, 
this angle corresponds to a distance of 10% in. that the 
straight portion of the leading edge recedes from a 
straight line at right angles to the fuselage center. 

Dihedral angle, center section, upper plane, 180 degrees. 
Dihedral angle of other wing sections 178 degrees. 

I'pper and lower planes are set at a 3-degree incidence 
angle, equal to rise in the leading edges of 4 13/16 in. 
The transverse and lateral center of gravity is located 
2 ft. 11 in. from the leading edge, at which point a hoist- 
ing eye is located. 

Centers of wing beams are located as follows: Front 
beam i' 1 ( in. from leading edge; beams 4 ft. 6 in. apart; 
trailing edge 2 ft. .S" s in. from center of rear beam. Wing 
chord, 7 ft. 7% in. 

Fuselage 

The fuselage is 27 ft. 6\'-> in. long; maximum width, 2 
ft. I- in. Maximum depth between longerons, 2 ft. 11 in. 
The nose extends 6 ft. 11 in. forward of the main planes. 
The observer's cockpit is located at the nose, and the 



pilot is located immediately below the trailing edge of 
the up|>cr plane. 

Location of vertical fuselage members are indicated by 
dotted lines on the drawing. The fuselage termination 
is IK in. high, formed by a strut which carries the central 
rudder and also supports the tail float 

Tail Group 

llori/.ontal stabilizer, 16 ft. in. across at the trailing 
edge. Width. I ft. " ._. in. The leading edge is Straight 
for a distance of 13 ft. I in., then curved in a 9 in. radius 
to a raked angle. It is non-lifting. Klcvators are 16 ft. 
8% in. from tip to tip. Maximum width, 3 ft. 8 in. 
Control posts located 6 ft. in. apart, one on each flap. 

The vertical fin is 3 ft. 2 in. high, and to it the central 
unbalanced rudder is hinged. The central rudder is 2 ft. 
3 in. wide. 

In addition to the central rudder, there are a pair of 
balanced rudders located 6 ft. in. to either side of the 
rin. These rudders have a maximum height of 3 ft. 2 in. 
and a width of 2 ft. 2 in. 

Float* 

Floats are arranged catamaran style, with centers 10 ft. 
in. apart. Each float 3 ft. in. wide, 19 ft. 1 Vj in. 
long and 2 ft. in. in overall depth. A step 3% in. deep 
is located 11 ft. lO'/.. in. from the front end. Struts to 
the fuselage are located at the following distances from 
the nose: 4 ft. S in.; 4 ft. 9 in.; 5 ft. in. The dotted 
and dashed line indicates the water line with the machine 
fully loaded with a weight of 5380 Ibs. 

The tail float is 19 in. wide, 4 ft 8 in. long and 11% in. 
deep. 

Motor Group 

Motor carrying struts are located 1 1 ft. 7% in. apart. 
The drawing shows the motors covered in with metal 
cowling. Propellers are 8 ft. 10 in. in diameter, rotating 
in opposite directions. 

The motors are Sturtevant model 5 A, rated at 150 h.p. 
These motors are 8-cylinder, 4-stroke cycle, water cooled, 
with a 4-inch bore and .">'. inch stroke. The normal 
operating speed of the crankshaft is 2000 r.p.m., and the 
propeller shaft is driven through reducing gears. The 
weight per h.p. of the motor is 3.4 Ibs. 

Fuel is consumed at the rate of 26 gallons per hour, 
and tanks have a capacity sufficient for an eight-hour 
flight 




^^H 
The Vickers "Vimv-1! 



type, biplane, equipped with two Holls-Hoycc 303 h.p. motors 



The Transatlantic Type Vickers " Vimy " 

This type of plane was made famous by the historic flight of Captain Alcock and Lieut. Bronton 



The wing span of the Vickers- Vimy Biplane is 67' 2" ' 
and the chord 10'-6", both wings, upper and lower, being 
identical in dimensions. The area of the upper wing is 
686 square feet, that of the lower 614, giving a total 
wing surface of 1330 square feet. The angle of incidence 
of both upper and lower wing is S^b", whereas the 




dihedral is 3. The surface of the ailerons is 2-1 '2 square 
feet. The areas in square feet of the control surfaces 
are as follows: tail plane, 11-1.5; elevators, 63; fins, 17; 
rudder, 21.5. 

The Vickers-Vimy is powered either by two 350 horse- 
power Rolls-Royce Eagle engines or 2 Salmon engines. 
It was one of the former type which made the successful 
trans-Atlantic flight. With the Rolls-Royce its weight 
empty, is 6,700 pounds; loaded, 12,500 pounds, witli a 
fuel capacity sufficient for 8.5 hours, or a distance of 835 
miles. 

The speed is 98 miles an hour, and an altitude of 5,000 
feet is gained in 15 minutes. The ceiling is 10,500 feet, 
with a military load of 2.870 pounds. The weight per 
square foot is 9.4 pounds, and weight per horsepower 
17.9 pounds. 




The transatlantic type Vickers " Viniy-Rolls " biplane 
CO 



Mil /ri -M( )T( )1{ Kl ) A KK< >1M . A N KS 




Til.- l.ouplii-.-til liiphmr, i-.|iii|.|ii-il with two Hnll-S-ott A-...I motor*. 




h'ronl virw of Louche nl twiii-niotorril tlyinjr hunt with two Ilnll-Siotl A -.'HI motor*. 




Tl 1. ral.am. \\hite "Bantam," with its span of JO feet, nrxt to a 20 pnswngrr Grahamc- White twin-motored l.iplnnr havinjr 

span of H9 fcrt. 



62 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A group of twin-motored A. V. Roe bombing planes. The machine on the extreme left is equipped with two Sunbeam aero en- 
gines, in the centre two Green engines, and on the right two Rolls-Royce engines. 

The Avro Twin Engined Bomber 



Fitted with the 230 h.p. Galloway B.H.P. Motors, this 
machine has the following performance when fully loaded 
with bombs, etc. 



Ileic/Jit 

'o 

5,000 
10,000 
15,000 
17,000 



Climbing Trial. 
Time 



min. 



19 </ 2 



57 



Military Load 
Rate of Climb 

800 ft./min. 

535 " " 

340 " " 

170 " " 

106 " " 



R.I'M. 
1,420 
1,420 
1,395 
1,355 
1,335 



Height 


5,000 
10,000 
13,000 
15,000 



Speed Trials 

Spted 
110 M.P.H. 
108 M.P.H. 
106 M.P.H. 
100 M.P.H. 
93 M.P.H. 



R.P.M. 

1,550 
1,540 
1,495 
1,450 
1,410 



This machine was designed as a long distance high 
speed bomber. It is a 3 seater twin engined tractor bi- 
plane. The power units, which are entirely independent, 
are mounted on the wings. One gunner is seated in the 
extreme nose of the body and is provided with a gun 
mounted on a rotatable mounting. Fitted in the front 
cockpit are the bomb sight and bomb release gear. A 
second gunner is seated well to the rear of the main 
planes, where he has an exceptionally good field of fire in 
every direction. He is provided with complete dual con- 
trol for the machine and two guns, one mounted on a ro- 
tatable mounting on the edge of the cockpit, and the second 
gun firing through the hole in the bottom of the body for 
repelling attacking machines coming up under the tail. 
The pilot is seated just in front of the leading edges of 
the planes in an extremely comfortable cockpit. 

Wings 
Dimensions 

Span of top wing 65 ft. in. The wings are.straight in plan form, with rounded wing 

Span of bottom wing 65 ft. in. j.jp S an( ] are made to fold, outside the engine units, thus 

Chord of top wing . 7 ft. 6 in. saving considerable shed room. The wing bracing is 

Chord of bottom wing m. d f tubular fe d inter pl ane struts and swaged 

Span of tail plane and elevators 18 ft. 1:1. 

Chord of tail plane and elevators 6 ft. in. streamline wires. The struts are faired off throughout 

Height overall 13 ft. in. their whole length by means of light wooden fairings 

Length overall 39 ft. 8 in. covered with fabric. Single bracing is employed, but the 

Gap of main planes . 7 ft. 3 in. wjng structure is so designed that all the main lift wires 

Area of main planes 022 sq. ft. are duplicated through the incidence wires, that is to say, 

Area of ailerons 128 sq. ft. tnat jf a f ron t ]jft wire were shot away, the load normally 

Area of tail plane .... 48.4 sq. ft. d b thi j would b transmitted through the 

Area of elevators 36.8 sq. ft. - v 

Area of rudder 24.5 sq. ft. incidence wire to the rear spar bracing. Ailerons are 

Area of fin 10 sq. ft. fitted to the trailing edge of both top and bottom planes. 

. The wings are covered with Irish linen sewn on to all the 

ribs, and doped in the standard manner. The wings are 

The following are the principal weights: built up of ribs made Qn a pate nted aluminum girder con- 
Weight of machine (light) 4,300 Ibs. struction, the top plane being in three sections, and the 

Petrol^ 120) gallons ... 866 Ibs. bottom wing in four sections. The inside sections of the 

bottom plane are built into the bodv, and are spcciallv 

Water (13%) gallons 13o Ibs. ' 

Pilot 180 ibs. designed to take the engine units, landing gear and plat- 
Two Passengers 380 Ibs. forms for standing on whilst attending to the engines. 

Guns 70 Ibs. The main wing spars are of spruce, spindled to an "I " 

Ammunition Ibs. section The ribs are bnilt of spruce fl alls , vs and 

Bombs 1,083 Ibs. 

stamped aluminum ties. 1 liese are riveted together to 

Total flying weight 7,200 Ibs. form a correct girder construction and are exceedingly 

Main planes surface loading (fully loaded) . . . 7.825 lbs./sq. ft. strong. The internal compression struts are of steel tube, 
Nominal engine loading lo.o Ibs./h.p. fitting on to special socket bolts which also take the brae- 



MULTI-MOTORED . \I.KO1M..\NKS 



ing plates for tin- internal bracing ties. The inti rn.-il 
bracing ties .-in- formed of swaged steel rods with in.-i 
rluni-il iiids .mil in designed l take tin tt:il drift nn the 

Willis win ii tin- machine is diving at limiting velocity. 

The trailing edges of the planes art compost d ,.| ,>\ il 
steel tubing, securely fasti-neil to tin- ril s. Tin- bracing 
plate and strut attaelmient on tin- wings are extremely 
lie it and simple. Tile eml of tin- struts are lilted with a 
snitalile hemispherical enil which tits into a specially de- 
signed cup headed dolt, the bolt also forming the attach 
ment for the bracing plate. This method of construction 
is patented. 

Engine Units 

Tin- power is supplied by two _':>(> h.p. Galloway B.ll.l'. 
Motors, driving din-et two airscrews 9 ft. 6 in. in diam 
i ter. The engines are mounted on special M-plv and 
spruce engine mountings which are l>uilt into the renter 
sections of the liottom wind's, forming an extremity lif(lit 
and rigid lias,-. The main petrol tank is mounted inimi- 
iliatelv l>< hind tin engine, anil behind the petrol tank is the 
oil tank. The radiator is mounted in front of the engine, 
and the whole unit is carefully faired off to reduce head 
resistance. A small auxiliary petrol tank is mount* d on 
the top plane just ai;ove the power units and is used for 
running the engine when on the ground and netting off. 
Tin petrol is fed from the main tank to the auxiliarv petrol 
tank, or direct to the carlmrctors of the- engine by means of 
a positive pump driven by a small windmill. The main 
tanks are provided with dial petrol level indicators, which 
;l\ r. id from tin- pilot's seat. It may be as well to 
point out here, that practically am existing type of engine 
can lie easily accommodated in this machine. Any engine 
from .'()() h.p. to .inn h.p. being suitable, machines of this 
type have been fitted with Rolls- Koyce. Sunbeam and 
dreen Motors, with very satisfactory results. Tin- engine 
controls are conveniently placed at eaeh side of the pilot, 
the two dependent throttle controls being on the pilot's 
right hand side, and the magneto controls on the left hand 
sidi The engine controls can IK- moved together or inde- 
pendently, as. for example, when a sharp turn is required, 
one throttle ean be left open and the other closed, so that 
the engine thrust helps the turn. I.cvers are also pro- 
vided for adjusting the carburetors for altitude. 

Body 

The body of the machine is of the usual box girder con 
strurtion. with spruce rails and struts and swaged steel 



rod.s for bracing. The body rails are stiffened by IIH .-HIS 
Ii wood formers in the Standard Airo in inner. 
This construction makes the rails extremely strong and 
obiiates the tendency ot the rails to warp. The body is 
of a good streamline lorm and proinlcs ample accommo- 
dation for (In- enw and the bombs. The nose of the 
fuselage is eon red with :: ply wood and the decks and 
iNimh compartment are lornnd ot the same material. Un- 
rest ot the body being eoiered with doped fabric carried 
OUT stringirs to preserie the shape. To permit the rear 
gunner to tire underneath the tail, a sp, ,-ial ^ at i, m.idi in 
the floor through the rear coekpit, and a long hole is ar 
ranged in tin floor through which a good view downward 
and backwards is obtained. When it is not rei|iiin d to 
use this opening, it is covered hi means of a sliding dooT. 
Steps are provided in the side of the body and a small light 
steel ladder, hung from the side of the machine, enables 
the crew to climb easily into their pl.i 

Tail Unit 

This consists of an adjustable tail plane, the angle of 
in. -nli nee of which ean be varied by the pilot whilst in 
flight, by means of the patent Avro tail adjusting gear. 
The elevators are hinged to the trailing edge of the tail in 
the usual manner. The fixed fin is fitted on top of tin- 
body . and hinged to the stern post is a large bal 
rudder. All the empennage members are built up of 
spruce and steel tubing and covered with doped fabric. 
The tail is braced by streamline steel wire*. 

Controls 

The elevator and aileron control is of the wheel and 
column type. The large hand-wheel being mounted ver- 
tically in front of the pilot on the top of the rocking col- 
umn. The rudder in operated by means of foot bar in the 
usual manner. All control surfaces are actuated by means 
of flexible steel cable passing over ball bearing pulleys. 

Landing Gear 

The landing gear in of uni<|u< design, weight and head 
resistance having lx-en cut down to the absolute minimum 
without sacrificing strength. The landing gear consists of 
two wheels mounted on tubular steel axles, which are at- 
tached by means of ball joints to the body. The landing 
shock in taken through a special shock absorbing strut as 
usually employed on Avro machines, and there is a diag- 
onal behind this, taking the backward loads imposed when 
landing and tax y ing on the ground. 




Hear view of the Avro twin-motored Itumliiiifr Hiplanr. 







K 





F 



5 o 





LAW50N TYPE'Cl 

TWIN LIBEBTY MOTOI2CD 

AEQAL TPAN5POCT 



Sca.le of l^eet 



s a 10 i? 14 1 



Mclaughlin 



64 



MULTI-MOTORED AKKui'l. .\.\K> 



Lawson Aerial Transport 

The giant I .aw son ' ( I " biplane was designed from i front and rear of the cabin. On the left su|. of the cabin 

strictly commercial point of v i, w forward of the wings an entrance door is provided. Tins 

The fuselage is built to accommodate :il pass, Hi;, rs and door is of such proportions that the usual method of 

all the details of its construction and performance char climbing or crawling into the machine is done awav with 
acteristics take into consideration the s ,|,l\ and comfort P . , 

of the pass, liters. . . 

Dual controls arc provided at tli< lorward , nd of the 
I he seats an naililv detachable and sleeping quarters: .. 

cabin. < out ml wheels are is in diameter ind ar, 

installed for a fewer number ol passengers when cruising 

mounted on a tube e\li nding from one side of the bod) 
for considerable disl.-im , s 

..... '" "'c other. 1 he wheels control the ailerons and ele- 
I he ten, ral specifications of the I. aw son Air transport . . 

vators, and the usual f, M it bar is BMO for the ruddi rs 

I -I arc as Follow s : , .. 

All control surfaces are interconnected and cables doubled 

General Dimensions | M t | 1( . n j| ( .,ons wood is used in the construction. l-'or 

Span, both pl.mes . . . .M ft. In. ,|,,. st .-dili/.ers and el, -valors both wood and steel an p 

Chord, both planes 9 ft. (i in. .... . . . .. . .. . . a . . 

. | (i ft 3 in rudders are nearly all steel. ror night Hying. CMC 

I.ciurtli ovtr.ill it. 7 in. lr ' I'glds arc supplied for the instrument hoard, interior 

ll.i.'lit overall U ft. in. ' of the cabin, and the wind's 

Areas Tail Group 

X,/. fV. The fuselage terminates in a steel tube stern post to 

Main planes, including ailerons . .I.TINI which is attached a rcar spar of the lower tail plane and 

Aill ' r "" s (l) also tail skid. The tail, of the biplane tvpe. is adjustable 

Stal.ili7.ers ( .') 17iJ 

i)iiri< . ,, 5 -$ to counteract any ofVCmMM in balancing which may in 

Kndilers (:l) 45 s1 "'- "'"' '" the large si/c of the machine, passengers 

A n ~j eg ln;l . v move freely alxuit the fuselage without any dis- 

Incidence of main planes 3 turbance to plane. Uuddcrs and elevators are of the bal- 

Did.-dral 1 anccd ty|>e. 

i.haek 6 e Landing Gear 

S ,i,ili/er settiii).' to \\\na chord 0" Ti I r j r 4 t aa" u 

I he landing gear is composed of two pairs of 36 by 

We 'ihts 8" wheels carried on large streamlined steel tube struts. 

M icliinc fully loaded .. 1^,000 Ibs. T | 1( . v ;lrt . attached under each engine in such a way as 

Performances to evenly take up the landing shocks with a minimum of 

('limit iii 10 minutes with full loud 4,000 ft. strain to the wings and fuselage. 

luijr 14,000 ft. 

( lliilinjr alible 1 to 8 Engines 

In, I duration 4 hours Two Ig-rylinder I.ilx-rty engines are used. They arc 

completely enclosed in nacelles at either side of the' fuse 

Main Planes loge. 

I S. A. ."> winu' section is used. Main planes are in Engines are placed in pusher position with profilers 

n sections The outer center section extends between M)' in diameter revolving in opposite directions. They 

the outer struts of either engine nacelle. The two lower rest on large ash beds internally braced by steel tubes. 

center sections run from the fuselage to outer engine Gas tanks are located in the nacelles. Kngines are 

! struts. equipped with separate controls to the pilot's cotnpart- 

Fuselage ment, where they may IK- operated separately or together. 

- its arc placed at windows at each side of the body, Effective milliters are provided which add greatly to the 

and an aisl, Itctwcen the seats allows passage from the comfort of the passengers. 



/ ' 



IIIUII 







THE FRENCH CAUDRON TWIN-MOTORED BOMBING BIPLANE 




A front view of a Caudron R 11 French Bombing Biplane. This machine is a three (3) seater and is driven by two Hispano- 

Suiza motors. 




French Caudron Biplane equipped with two Hispano-Suiza motors. 




The Caudron R 11 type of French Bombing Biplane. Twin motored, it carried two and sometimes three men. The nacelle 

projects considerably in front of the plane thereby insuring a good view. 



66 



MULTI-MOTORED AKKOI'LAM.S 



157 



The Friedrichshafen 
Twin-Motored Biplane 




This machine is ;i weight carrying type and was used 
for bombing purposes. It iniriii.-illv carried a crew of 
four. The cot -kpits wire intercommunicating, so thnt the 
personnel could change plan s. etc. 

The tnt.-il weight of tin- empty machine is 5930 pounds. 
load -.'?'..'(> M>s. Maximum load 8616 Ibs. 



sq. ft. 



General Description 

The general (lesion of the machine is shown in the at- 
tached drawing, which gives plan and front and side ele- 

vations. 

The principal dimensions arc as follows: 

Spat, .......................................... 78 ft. 

M .ixiiiiiini ehnnl ................................ 7 ft. fl in. 

Gap ........................................... 7 ft 

Dihedral illicit- in the \.-rti.-al plain- ............. ly,' 

Dihedral :IML'|I- in the hnri/.iint.il pi me ........... 6* 

nain planes ...................... 934.4 

\n-;i nf upper 111. mi planes without flap ......... 490 

Area of lower niiiin planes without flap .......... 451.4 " 

I. o nl per si|ii:irr fm>t .......................... 9.2+ His. 

\Veinht per horse pimer ........................ 16.6 His. 

\rr i of (lap of upper wing ..................... 21-6 ! ft. 

llalancc area ................................... 1 .8 

of ll.ip on lower v> ing ...................... 16 

Ilillanee an-a ................................... 1.56 

Tulal area of lived tail planes ................... 47.6 

I urea of elevator-. ......................... 3i 

H.il.uice area of one elevator .................... 1.7 

Ana of (in .................................... iO 

.if rudder ................................ 19.3 

II. il am i area of rudder ......................... 3 

Maximum cross section 01 body ................. 19.2 

Horizontal area of body ............. .......... 133 

Vertical area of liody .......................... 131.9 

over all ............................. . .. 4? ft 



The machine is built up upon a central section, to which 

attached the forward and rearward portions of the 

fuselage and the main planes. This central section com- 

prises the main cell :r caliin of the body, containing the 

tanks, bomlis. etc. It also embraces the engines and the 

tral portion of the upper and lower planes. The 

latter, together with the engine struts, are largely built up 

of still tube, as is also the landing gear. 

Tin central portion of the body, which measures 4 ft. 
across by I ft. S in. in height, consists of a box formation 
made of plywood, strengthened by longerons and diag- 
onals, anil transversely stiffened by ply-wood bulkheads. 
The bulkhead farthest forward acts as an instrument 



board, behind which are side by side the seats of the pilot 
and bis assistant. The former has a fixed upholstered 
si at. whilst that of the latter is folding, consisting of a 
light steel tubular framework with a webbing backrest. 

I nderneath these two seats is the lower main petrol 
tank. Behind this cockpit the body is roofed in with ply 
wood, the rear part of which roofing is detachable so as to 
give access to the second main petrol tank, which is at the 
rear end of the main body section. By this means a small 
caliin or covered passageway is provided, at each side of 
which are the racks for the smaller bombs. 

Central Portion of Wings 

The central and non-detachable portion of the upper 
plane has a span of 19 ft. 5 in., whilst at each side of the 
nacelle the lower plane fixed portion measures 7 ft. 8 in. 
The main wing spars in this central portion arc of steel 
tube, roughly 2 in. in diameter, with a wall thickness of 
1/16 in. 

These spars are braced by steel tubes arranged in the 
form of an X, the manner in which the bracing tubes arc 
attached to the main spars being shown in the sketch 
Fig. 1. 

The lugs are built up by welding, and are pinned and 
riveted in position, the joint being of the plain knuckle 
type. 

The upper surface of the lower plane is, so far as the 
central section is concerned, covered in with three-ply 
wood. 

In this portion the main ribs are of three-ply, with 
spruce flanges. Between each main rib is a cut-away rib, 
the design of which is shown in the sketch Fig. 2. This, 
unlike the main ribs, is one piece of wood, and not built up. 
For the greater part of its length it applies to the top 
surface only, being cut away to pass clear of the cross 
bracing tubes. 

The plane is further stiffened with transverse members 
consisting of three-ply panels between each rib strength- 
ened by grooved pieces top and bottom. The latter are 
attached as shown in the sketch Fig. .S, and the attachment 
of the flanges of the main ribs is shown in Fig. 4. 

The central section of the up|>er main plane is in one 
piece and is covered top and bottom with fabric. In order 
to facilitate the reinovnl of the engines, detachable panels 
measuring 1 ft. 1 1 \' in. long by 1 ft. 8 in. deep are let into 
the trailing edge immediately over the engine bearers. 
These panels are socketed in front, and at the rear are 




Line drawings of the Twin-motored Friedrichshafen Bombing Biplane. 




Sketches showing details of construction of the Friedrichshafen Bomber. 

68 



.MlI.Tl-MOTOKI.l) AKKOl'I.ANKS 



B8 



juiliril up at tin- trailing edge with I section sheet steel 
clips anil l.olts. 

The struts which connect the top of tin- nacelle to the 
uppi-r plain- art tiilinl.-ir and of streamline section, as are 
also tin- engine bearer strut-.. A section of on. of tin- 
latter is ^ivi n in I I IT- -"'- 'I'll' 1 tliit-knc.ss of the wall is mi. 
sixteenth of an inch. 

The method of attaching the lower i-nil of tin- engine 
struts to the tuhular steel spars is shown in the sketch Fig. 
<;. from whi.-h it will be seen that a weldc-d Y socket it 
us< d and secured hv a pin joint, the ends of the pin acting 
as -meliorates | c ir the attaehinent of tin- bracing wires. 

'I'his sketeli also shows the lugs which respectively sup- 
port the detachable portion of the main planes an. I tin- 
vertical strut of the landing chassis. The engine hearer 
struts are pushed into the i socket and pinned in position, 
the pins lieinit afterwards hra/.ed into the socket. At their 
upper ends the engine struts are (ixed to the top plane 
spars with pin joints, as shown in Figs. 7 and 8, the attach- 
ment differing according to the number of wire bracings 
that art- to he taken to each joint. 

Construction of Wings 

The detachable portions of the wings are fixed to the 
renter section by pin joints, one part of which is shown 
in Fig. t>, the male portion being represented in Fig. 9. 
The chord of the wing in the line of flight varies from 
approximately 7 ft. 8 in. to ~ ft. .'. in., and the wing sec- 
tion is shown shaded in I'ig. 10. In order to provide a 
basis of comparison the l( A.I . \^ wing section is super- 
imposed and drawn to the same scale. 

The main spars are placed one meter apart, the front 
spar being -J7'-' iiims. in the rear of the leading edge. Both 
spars are of the built up ln>x type, as shown in Figs. 11 
and I -'. Tin- former is the leading spar and the latter the 
rear spar. These spars arc of spruce, and each half is 
furnished with several .splices, so that the greatest single 
1'iigth of timber in them is not more than 11 ft. The 
splices, which occur in each half alternately, are of the 
plain bevel type about 1 .1 in. long and wrapped with fabric. 
A t.ibric wrapping is also applied at short intervals along 
the spar. 

Internal cross bracing between the main spars is af- 
forded by steel tube cross memlxT.s and cables attached us 
shown in the sketch Fig. 9. 

Tin- main spar joint consists of a steel plate 1!) mms. 
thick embedded in the spar end and held in position by ~> 
bolts, which pass through a strapping plate surrounding 
,| of the spar. This plate also carries the attach- 
ment for the bracing cable and is furnished with a spigot 
which locates the bracing tub*-. It will be seen that at this 
point the spar is provided with ta|M-rcd pat-king pii 
hard wood glued and held in position by fabric wrapping. 
The main ribs are placed :i(i() mms. apart. Between 
them are auxiliary formers, consisting of strips of wood 
.'i> mms. x in mms. thick, which run from the leading 
to the rear spar. The main ribs consist of ply wood 
-ockcttcd into grooxed spruce llangcs. which are 
tapered off as shown in Fig. k except where they are met 
by a longitudinal stringer. The leading edge is solid wood 
moulded to a semi-circular section of approximately OS 
. d : ameter. Where the rib web abuts against it, pack- 



ing pieei s are glued i ach side. Hetwieii the main spars 
the web of the rib Is dn id< d In thr .1 strips into 

lour panels and in each of tlnse it is perforated, hiving 
an edge til round about 7- mms. wide. 

As shown in 1 -'ig. !>. the upper flange of the main ribs is 
carried char of the hading spar by means of packing 
pieces. In the case of the rear spar, packing pieces arc 
also used under the rib flange ns shown in Fig. 12. 

The lower main planes for a width of about 2 ft. 3 in. 
at their inner end an- covered as to their top surfaces with 
three ply wood. 

The interplnne struts arc attached to the main spars by 
joints of the type shown in Fig. I k. This, it will be seen. 
follows the typical (uriiian practice of partially universal 
jointed mountings for the cable attachments. At the 
points of attachment of these strut joints, suitably tapered 
packing pieces of hard wood surround the spars, which at 
these points arc also wrapped with fabric. 

Struts 

Outside of the center section the interplane struts are of 
wood built up, ns show n in the section Fig. 1.1, of five sepa- 
rate pieces. The curved portions arc of timber which has 
not yet been identified, but is apparently of poor quality. 
The cross web is of ash. The strut is wrapped at fre- 
quent intervals with strips of fabric and is fitted with a 
socket joint of the type shown in Fig. 16. The outer pair 
of struts are of smaller section than the main struts, but 
are built up in a similar manner. Their section is 125 
mms. x 10 mms 

Ailerons 

The framework is principally of welded steel tube 
wrapped with fabric. 

A notable point is the thick section of the leading edge 
of the balanced |x>rtion, us shown in Fig. 17. 

Fin and Fixed Tail-Planes 

The framework of these is steel tube and in the case of 
the tail-planes wooden stringers running fore and aft are 
arranged at intervals. The tail-planes are supported by 
diagonal steel tubes of streamline section, on the under 
side of which sharp steel points are welded to prevent 
these stays being used for lifting purpose*. 

Elevators and Rudders 

Tin- framework in each ease is of steel tube, the main 
tube being 35 mms. in diameter and the remainder 15 mms. 

Bracing 

Throughout the wings, both internally and externally, 
the bracing is by means of malt is) rand steel cable. 

Fuselage (Rear Portion) 

At the after-gunner's cockpit the section of the fuselage 
has a rounded top. which is gradually smoothed down into 
flat. The section, for the greater part of the length, U 
rectangular, and the frame is built up in the usual man- 
ner with s<|iiare section longerons and \crticals. the joints 
being arranged as shown in Fig. 18. The cross bracing 
wires along the sides, top, bottom, and diagonal are of 
steel piano wire and are covered with strips of fabri. 



The inside of the front cockpit. 




View looking down the inside of the 
fuselage, showing trap door and after- 
gunner's folding seat. 



Flo. 19. 





Flo. It. 



FIG. 12. 



Details of construction of Friedrichshafen Bomber. 
70 




Fie. 23. 



Mn.TI-MOTOKKI) A KK< HM.ANKS 



71 



shown in this sketch, where they In adj ic.-nt to tlir fabric 
fuselage covering. 

Tin- vertical and liori/.ontal compression members are 
located by spigots. Tin- joint consists of plate which 
completely Mil-rounds the longerons, its two mil-. being 
rhcted together to torin a diagonal bracing strip. 1 or tin- 
last few liit ;it tin- tail the fuselage is covered with thin 
three-ply. 

Tin- fuselage is coMTcd with f.-ilirii-, wliicli is held in 
position l>\ i 1. icing iindrrni-atli and is consri|iiciitly hodilv 
n movable. 

'1'ln- lliKir of tin- after gunner's cockpit is elevated above 
the hottoin of the fiis' l.i^i I iniiiediatel V underneath this 
cockpit is a large trap door, shown liy dotted lines in the 
plnn view of the aeroplane. This is hinged at its rear- 
ward end and furnished with two large celluloid windows. 
It is held in its " up " position by a long spring and a snap 
clip. No me ins could he found bv which it could he ii\. ,1 
in its dosed position. As footsteps are provided for all 
the cockpits, this trap door is evnlentlv not intended for 
ingr. *s ,i l( | e^n-ss. It rould he employed in connection 
with a machine pin tiring backwards, as in the (iotha. but 
no iiiachini gun mounting was fixed in this machine for 
this pur). 

Tin- rear portion of the fuselage is attached to the cen- 
ter section of the body liy a clip at each corner. This is 
shown in 1 ig. 1!'. The rear portion carries a male lug, 
which engage s with the two eyes, and is held in position 
,fhs holt. lour other l>olts in tension pass through 
the sheet metal clip, as shown in the sketch. In each case 
the hit's arc furnished with sheet steel extensions which, 
as shown in the sketch Fig. 19. are sunk flush into the top 
mid bottom surfaces of tin- fuselage longerons and are 
there held with three holts. The corner joint is welded 
ii i-l. and there is an additional diagonal sheet steel 
point which serves the secondary purpose of providing an 
anchorage for the bracing wires. 

As this fuselage joint is level with the plane of rota- 
tion of the propellers, it is armored both on the nacelle and 
on the rear portion of the fuselage with a hinged covering 
of stout sheet steel lined with felt. A plate of armor a 
foot wide also extends down each side of the nacelle at this 
point. 

Forward Cockpit 

This is attached to the main body by four bolts with 
dips similar to those just described. It consists of a light 
ien framework, covered throughout by three-ply. 

The cock-pit can be divided off from the main cockpit 
by means of a fabric curtain. Its occupant is provided 
with the folding seat, and manages a gun and the bomb- 
dropping gear. 

Engine Mounting 

The engine bearers have the section shown in Fig. 20, 
and arc each built up of two pieces of pine united by 
s. On their top surface they are faced with ply- 
wood, and at the bottom with ash. A strip of ash applied 
to the upper outer corner of the bearer gives it an " L" 
section, and has screwed into it the threaded sockets for 
tb set screws of the lower part of the engine fairing. 
The engine bearers taper sharply at each end. They are 



mounted on the " V " struts by means of acctvh in wehhd 
brackets, constructed as shown in sketch. Fig. J 1 . These. 
it will IK- seen, are of box form, and form a liner round 
tin streamline tube. 

The engine cow linn is a particularly fine piece of work, 
and two views are given in sketches 22 and 23. Tin- 
lower portion is attached to the i ngine hearer* by set 
screws, but the up|M-r part is readily d tachable, being 
furnished with turn buttons. Tins cowling allows the 
cylinders of the engine to be exposed to the air. A large 
scoop is placed in front, so as to permit a free flow of air 
OUT the bottom and sides of the craiikchamucr, whilst at 
the rear three Inrgc trumpet shaped cowls arc provided so 
that a draught of air is forced against the craiikca.s<- in the 
neighborhood of the carburetor air intake. In the rear the 
fairing abuts against the propeller nave, whilst in front it 
is attached to the radiator. It will IK- noticed that at each 
side of the radiator are narrow air scoops, the object of 
which is to promote a draught past the oil tank and front 
cylinder heads. 

Engines 

Theraiotors are the standard 260-h.p. Mercedes with six 
cylinders in line. Full details of this engine have been 
published, and it is only, therefore, necessary to notice 
one or two points in connection with the installation. 

A new departure is the interconnection of the throttle 
and ignition advance controls. This is carried out in tin- 
manner illustrated diagrammatical ly in Fig. 24. It will 
be seen that a considerable movement of the throttle can 
be made independently of the ignition advance. In the 
Mercedes carburetor the throttle is so arranged that it 
cannot be fully opened near the ground without providing 
too weak a mixture, and it is thought possible that the full 
ignition advance is not obtained until this critical opening 
is reached. 

On several German bombing aeroplanes grease pumps 
for lubricating the water spindle have been found. Fig. 
25 shows the design as fitted to the Friedrichshafen. It 
consists of a ratchet and pawl operated grease pump, se- 
cured by a bracket to one of the engine struts, and worked 
from the pilot's cockpit by a lever, and a stranded steel 
cable passing over a pulley, the pawl being returned by a 
long-coiled spring. 

The exhaust pipe is of new design, although it incor- 
porates the well-known expansion joints attached to the 
flanges. It is fitted with what amounts to a rudimentary 
silencer, whereas in previous machines of a similar type to 
the Friedrichshafen an open-ended exhaust pipe was used. 

Radiators 

Each radiator is provided with an electric thermometer 
fitted into the water inlet pipe, us shown in sketch. Fig. 
J7, these thermometers being wired up to a dial on the 
dashboard, which is furnished with a switch, so that the 
temperature of either radiator can be taken independently. 

The radiators consist of square tubes to the number of 
4134. and measuring roughly mms. each way. 

The radiator block is V shaped in plan, and each is 
provided with a shutter which covers up a little more than 



Construction details of the Friedrich 
shafen Bomber. 




Kio. 32. 



Main landing chassis, tail skid and ma- 
chine gun mounting in the front of the 
fuselage. 



MILTI-MOTOKKl) AKKOl'I.ANKS 



a third of tin- cooling surl u i . This shutter is fitted with 
;i stop, so Unit when fully n|)i-iifd it lirs ill tilt- line ot 
flight of tin- :ii-ro|)laiir. It is o|n-in-d or clos. ,1 :u , -onling 
In ciri iimstances liy tin year, show M in tin sketch. I || 
of Inch the h indie is iniiunted on the roof of the nacelle, 
iniinriliatelv behind the pilot's seat. Three positions ar< 
provided for the handle, which operates tin two shutters 
simultaneously Iv means ot return eahles. 

Iminediati 1\ .ilio\e the main radiator, in. I let into tin- 
upper main plain- between the front spar ami the I. idiii:: 
i .In. . is a small auxiliary tank, illustrated 11 
This is furnished with a trumpet shaped \ent in the direc- 
tion of the line of flight, and is furnisln d with two oiith Is, 
one to the Inad of the main radiator, ami the other to the 
water pump. The function of this tank is evidently to 
it the pump from priming. 

Oil Pump 

Tin main supply of oil is carried in sumps forming part 
of the hase chamber. A secondary supply of oil. from 
which a small fresh cliarije is drawn at every stroke of tin- 
oil pump, is contained in a cylindrical tank supported 1>\ 
brackets from the engine struts, and placed immediately 
In-hind the radiator. This tank has a capacity of 25 
liters ;, i _. gallons. Kach tank is furnished with a glass 
level. w Inch is \ isihle from the pilot's seat . 

Petrol Tanks 

The two main tanks which are placed, one under tin- 
pilot's seat and the other at tin- top rear end of the nacelle, 
contain J7 11 liters ."i!i.. gallons each, and arc made of 
hri". I ich is provided with a Maximal! level indicator, 
which employs the principle of n Hoat operating n dial by 
means of a cable enclosed in a system of pipes. 

A hand pump is fitted conveniently to the pilot, and 
pressure is normally provided by the pumps installed in 
each engine. An auxiliary tank, holding approximately 
l:i gallons, is concealed iii the upper main plane, not imme- 
diately over the nacelle but a little to the left side. This 
auxiliary tank is fitted with n level, as shown in Fig. 29, 
which is visible from the cockpit. The auxiliary tank 
nppiars to be used only for starting purposes. It is cov- 
ered with a sheet of fabric held in position by "patent 

.' Ts." 

Engine Controls 

Kiinning from each engine to the nac-elle is a horizontal 
!iit. containing the various engine controls. 
ion showing the arrangement of these inside the fair- 
ina is itiv.n in the sketch. Fig. 30. The leading edge of 
the streamline easing consists of a steel tube, to which are 
weld-d narrow steel strip brackets, to the rear end of 
which are bolted thinner strips which are hinged in front 
to the tuln-. The whole is then enclosed in a sheet alumi- 
num fairing. 

Through the leading tube passes the throttle control rod 
h engine, the two throttles being worked either to- 
gether or independently by the ratchet levers, shown in 
I. Tlnse are mounted on a shelf convenient to tin- 
pilot s left hand. This control requires a considerable 
number of bell cranks and countershafts, but was notice- 



ably trie t re. in backlash. The throttle is opened by tin- 
pilot pulling the levers towards him. 

On tin dashho-ird an !.. r. volution counters and two 
air pressure indicators. Tin metal parts ol tins, dials are 
p-iinti d n il lor tin li It i nuiin am! i;n . n for tin right, and 
tin same coloring applies to the magneto switches, one of 
which contains a master switch which applies to both 
in mm tos on both i urines. 

Piping 

The various sv stems of piping are distinguished by 
1 ii.g painted dilnr. nt color., thus the petrol pi|M-s are 
* lute, arrows licing also painti d on (him to show the 
direction of How; air pressure pipes arc blue, ami | i 
for cable controls gray. 

Propeller 

The prop Hers are each 8.08 meters in diameter and 
are made of nine laminations, which are alternately wal- 
nut and ash, except one which appears to be of maple. 
The propeller has the last 20 ins. of its blade edged with 
brass. The pitch is approximately 1.8 nieti rs nnd the 
maximum width of the blade '-'-JO millimeters. 

Controls 

Only one set of control gears is fitted, but as pointed out, 
tin- seating accommodation is so arranged that any of the 
crew can take charge if, and when, necessary. 

The elevator and aileron control is shown in sketch Fig. 
32. It consists of a tubular steel pillar mounted on a 
cranked cross bar at its foot. The ailerons are worked 
by cables passing over a drum on the wheel, whence they 
descend through fiber (juidcs on the cross bar to another 
wheel mounted on a countershaft below, from which they 
are taken along inside the leading edge of the lower wing 
and finally over pulleys up to the aileron levers on the 
top plane. The latter are partially concealed in slots 
let into the trailing edge of the wing. The upper and 
lower ailerons arc connected by means of pin jointed 
tubular steel struts of streamline section. 

It will l-.e observed from Fig. 82 that a locking device 
whereby the elevator control enn l>c fixed in any desired 
position is tilted, and consists of a slotted link which can 
be clamped by a butterfly nut to the control lever. This 
link is hinged to a small bracket attached to the panel 
below the pilot's seat. 

Fig. M shows the rudder control, from which cables 
are taken over pulleys and through housings in the nacelle 
and finally to the end of the fuselage. The cranked rud- 
der bar is of light steel tube and is arranged to be placed 
in the pivot box in either of two positions. It is furnished 
with light steel tubular hoops which act as heel rests nnd 
are adjustable. A locking clip is fitted on the floor of 
the cockpit so that the rudder can be fixed in its neutral 
position. 

A novel type of trimming gear is an interesting item 
of the control. Movement of cln elevator control from 
the normal upright |x>sition of the stick is made against 
the tension of one of two springs which can be alternately 
extended and relaxed by means of a winch connected to 
them, as shown in the diagram. Fig. 81. Normally these 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



springs tend to bring the control stick back to a central 
position, in which the elevator lies flat, but if one of the 
springs is tensioned by winding up the winch in clock- 
wise direction, the position to which the stick will tend 
to come when released will be such as to set the elevator 
at a positive angle. This winch gear, which is illustrated 
in Fig. 3:5, is mounted on the right-hand side of the nacelle, 
and is therefore under the command of the pilot's com- 
panion. 

The crank is furnished with a locking pawl, which 
engages with a ring of small holes bored in the plate of 
the winch. The steel springs used in conjunction with 
this apparatus are some 3 ft. long and about % in. in diam- 
eter. The inscription behind the winch read : 

Nose heavy Right wind. 

Tail heavy Left wind. 

Landing Gear 

As might be expected, the landing gear on this machine 
is of massive proportions. Two vertical streamline sec- 
tion wood-filled tubes descend from the center section 
wing spars, immediately under the engine, to a bridge 
piece or hollow girder made of welded steel. Through 
an oval hole in this girder a short axle carries two 965 
mms. x 150 mms. wheels (38 in. x 6 in.). These work up 
and down against the tension of a bundle of steel springs 
about 1/2 in. ' n diameter and made of wire approximately 
1-16 in. thick. 

The steel girder is extensively pierced for lightness, 
and the edges of the holes are swaged inwards. The axle 
is prevented from moving sideways by plates, and is pro- 
vided with short steel cables which act as radius rods and 
connect it to the front of the girder. The whole of the 
box girder is covered in with a detachable bag of fabric, 
which extends up to the small cross bar mounted imme- 
diately above the girder. 

Mudguards are provided behind each landing wheel for 
the purpose of preventing any mud or stones dislodged 
by the wheels from coming in contact with the propellers. 

From the front and rear of the box girder streamline 
tubes are taken to the ends of the main wing spars, where 
they abut against the nacelle, and these diagonals are 
further braced with streamline steel tubes. Both the 
vertical and diagonal tubes are held in split sockets so as 
to be easily replaceable if damaged. 

In addition to the four main landing wheels, a fifth is 
mounted under the nose of the fuselage. This wheel is 
760 mms. x 100 mms. (30 in. x -1 in.). It is mounted on a 
short axle, which is capable of sliding up and down slots 
in its forks against a strong coil spring, and it is also 
capable of a certain amount of lateral movement along 
its axle, also against the action of two small coil springs. 

The tail portion of the fuselage is protected by a fixed 
skid made of wood but shod with a steel sole. This is 
fitted with a small coil spring contained inside the fuse- 
lage. 

Wiring 

The whole of the wiring system on the machine is very 
neatly carried out. There are three main systems ; firstly, 
the ignition wiring, which is contained for the most part 
in tubes of glazed and woven fabric ; secondly, the heating 



system, for which the wires are carried in flexible metal 
conduits ; and, thirdly, the lighting system, in which a thin 
celluloid protective tubing is used. Wires are run from 
the nacelle along the leading edge of the upper planes 
to points level with the outermost strut. Here they termi- 
nate in a plug fitting placed behind a hinged panel. Ap- 
parently lamps are intended to be served by the circuit. 
Immediately in front of the pilot's seat a universally 
jointed lamp bracket is mounted on the outside of the 
nacelle. The exact purpose of this lamp is not known, 
as it could not illuminate any instruments. 

Armament 

Both the forward and rear cockpits are furnished with 
swivel gun mounts carrying Parabellum machine guns. 
These mounts consist of built-up laminated wood turn- 
tables working on small rollers, and carry a U-shaped 
tubular arm for elevation. This arm is hinged to a 
plunger rod working through a cross head, and arranged 
so that the arm is normally pulled down flat on the turn- 
table by a coil spring. The plunger can be locked in 
any of a series of positions by means of a bolt operated 
by a hand-lever through a Bowden wire. A second lever 
allows the turntable to be locked at any desired point. A 
perforated sheet-metal shield protects the cross head and 
spring. Small shoulder pads are fixed on the turntables, 
of which that in the forward cockpit has a diameter of 
2 ft. 1Q1/2 in., whilst in the rear the diameter is 3 ft. y 2 in. 

The after-gunner is prevented from damaging the pro- 
pellers by two wire netting screens, supported by tubular 
steel brackets, placed on either side of his cockpit. These 
are sketched in Fig. 36. 

In addition to these two guns, provision is made for 
mounting a third in front of, and to the right of, the 
pilot's cockpit, where it could be managed by his com- 
panion. For this purpose a clip is provided immediately 
under the coaming of the nacelle, and the handle of this 
protrudes through a slot in the dashboard. The clip 
works on the eccentric principle, and appears to be self- 
locking. Its construction is shown in detail in Fig. 37. 

A rack for Very lights is mounted on the outside of 
the nacelle convenient to the pilot's companion. 

INSTRUMENTS 

Airspeed Indicator 

Considerable interest attaches to the fact that this 
Friedrichshafen Bomber is the first enemy machine 
brought down which has been found provided with an 
airspeed indicator. This is of the static type, embody- 
ing a Pitot head of the usual type. The indicator has a 
dial of large size, and is altogether a much more bulky 
instrument than any for a similar purpose used in British 
machines. An investigation of its mechanism is being 
made. 

Altimeter 
This is of the usual type, reading to 8 kilometers. 

Level Indicator 

This is a somewhat crudely made device, employing 
two liquid levels, as indicated in the diagrammatic sketch 



MULTI-MOTORED . \KHoiM.. \M-.S 



75 



Fig. 38. It will be seen th.it tin- reading uixcs tin- pilot 
an exaggerate i! idea of tin- angle nf mil. Tin glass tiiln-s 
art- sealed u]>, and contain n d irk blur liquid. 

Revolution Counters 

Tin- dials i;i\c readings from ;(IKI to HIiici r.p.ni. The 
sector In tw.eii l.;ou and l.'.oii i, painted Mark, and these 
figures an marked with luminous compound, as also is 
tin indicating hand. 

Air Pressure Gauges 

Tlu-M- r.-ad from u to o.~. kilogrammes per square ccnti- 
meter. Thin is a r. d mark ajr-iinst tin figure 0.25 kg. 

Electric Thermometer Dial 

This dashboard instrument consists of a box-type me- 
ter, the dial reading from II to loo ,|, - ( The figures 
and ': are accentuated liy red marks. A switch at tin 
side of the l>o\, having positions marked 1 and "2, allows 
the temperature of either radiator to be read. 

Petrol Level Indicators 

These art ,.l the \Ia\iinall type, and employs a float 
immersed in a tubular guide in the tank. This float com- 
municates iu motion to a tinker working over a circular 
dial, by means of i thin cord passing over pulleys. These 
are incasid in pipes, which are under the same pressure 

as (he tank. 

Electric Heating Rheostat 

This is illustrated in Fig. 39. It is marked Aus (off), 
Schwach , xxiak>. Stark (strong). There arc two sep- 
arate resistance coils. , imMing th. rheostat also to per- 
form the function of a change-over switch. 

Wireless 

The machine is internally wired for wireless, and the 
left hand engine is provided with a pulley and clutch 
for drix-ing the dynamo. Reference to Fig. 22 will show 
that this is designed to be mounted on a bracket carried 
by the outside front engine bearer strut, and that the 
engine fairing is molded to receive it. 



Bombs and Bomb Gear 



At each side of the cox end in passage .iy in the nacelle 
are l.omb racks capable of holding five *3-pomid,r (12 
kg. ) bombs. 

I nderneath the naeell. an , -irrieil two large tubular 
ir.m.s. lilted with cradles of steel cable, and furnished 
with the usual form of trip gear. 

These racks would, it is l.elicxcd, l>e capable of SUp- 
portin- a :;IMI kg. bomb apiece. The homlis carried, how- 
c\cr. exidently xary with the radius of action ,,,,r which 
the aeroplane has to operate. The Inr^e racks are not 
permanently attached to the nacelle, but |x he r. 

moved as required. 

Inside the front cockpit from which the release of the 
bombs is coiiductid. there are s, MII triers for the small 
bomb racks and two levers for the lar^e l>oml> trips. The 
cables for this gear are carried under the floor, and are 
painted different colors for distinction. 

Bomb Sight 

The homb sjjfht carried on tin machine presents no new 
features, and is of the ordinary German non-precision 

type. 

Fabric and Dope 

Two entirely different kinds of fabric are employed in 
the I'riedrichshafcn machine. The wings are covered 
with a low-grade linen of the class which is employed on 
most of the enemy machines. It is white in color. Com- 
pared with that of British fabrics, the tensile strength is 
fairly good. 

This fabric is covered with a cellulose acetate dope, 
and is camouflaged in large irregular lozenges of dull 
colors, including blue-black, dark green, and earth color. 

The other fabric, which is applied to the fuselage, tail 
planes, rudder, elevator fin, and landing gear, is appar- 
ently a cheap material, much inferior to British fabrics 
designed for a similar purpose. This fuselage fabric is 
dyed in a regular pattern of lozenges, the colors being 
hardly distinguishable from black. The dope is acetate 
of cellulose. 



GOTHA 
TWIN ENGINE BIPLANE, TYPE GO. G; 




TA/1KS. 



76 



Mil /n-.M( >T( )H KI ) A KK( )IM ,.\ X KS 



77 




\ Ciotha twin -iiuitured I'li-hrr Hipl.inr. 



The Gotha Twin Motored Biplan 
Type GO. G5 



Tl..- ,1, tails of tliis machine do not differ to any great fiord 

xt.-nt from tlms,- of th<- usual German construction. Ow 

Thr p-nt-ral drtails of this plane are: KnKi"<- rrnt.-rs ............... II ft. 

, ,. Knirlncs (Mercedes) ........... 360 h.p. each 

.spa,, ,!,, plan,-) ,,v,-r tips of P] ft. S,-t l.m-k of plan,. ............. 4' 

I'roprll.-r (diainrtrr) ........... 10 ft. 2 In. 

Span (l,,,tt,.,n plan,-) ^^ Qf undpr ca whw|g rf f , , n 

Imp ........................... * II* 



" 2 '/ 'n. to 7 ft. 6 In. 
11 fi ' 



f , , % 



rhrec virw^ nt the German Gotha 
twin-motored Biplane. 




GERMAN A.E.G 

TWIN ENGINED 520\? 

BOMBING BIPLANE 




MULTI-MOTORED AKKoi'I. .\M.s 



Two ii w. n," Hi.- (Irrinni \. I''.. (' 
twin -inoton (I lli|i|,iiir. 




The German A. E. G. Bombing Biplane 



Fundamentally tlie A. E. G. bomber resembles the 
(lot ha biplanes. In dimensions, however, the two ma- 
chines iliHVr considerably, the Gotha being somewhat 
larger. Also the A. K. (i. lias its two airscrews placed 
in front of the main planes, whereas in the Gotha they 
are " pusher " screws. As in tlir (iotlia. the wings of the 
A. I. (i. are swept back at a 5 angle and are also placed 
at a dihedral angle, which appears to be greater in the 
bottom than in Ihe top plane. The span, it will be seen 
from the scale drawings, is the same for both planes, and 
amounts to .1 7 ft., while the overall length is about 30 ft. 
<! in ; chord, 7 ft. in.; area 800 sq. ft.; gap, 8 ft. 6 in. 
7 ft. ~> in. The ailerons, which are of a peculiar shape, 
are fitted to the top plane only, and are operated by a 
crank lever working in a slot in the plane. This arrange- 
ment would appear to be in general favor with German 
designers, whereas it is rarely or never met with in Allied 
chines. 

The tail planes, which are of the monoplane type, con- 
sist nf fixed stabilizing planes with an area of SO sq. ft., 
and a vertical fin, to which are hinged the elevators and 
rudder respectively. Both elevators and rudder have for- 
ward projections in order to partly balance them, thus 
relieving the pilot of a certain amount of the strain of 
working the controls. Maximum height of rudder, 6 ft. 
9 in.; area 17 sq. ft.; maximum span of elevators, 12 ft. 
ii in.; total area, 25 sq. ft. A tail skid is fitted under the 
sti-rn of the fuselage, and is sprung, not by means of rub- 
ber shock absorbers as is usually the case with our ma- 
chines, but by means of coil springs. The same is the 
case with the landing chassis, where coil springs arc also 
us< d instead of rubber. Whether this " indicates a short- 
age of rubber " in Germany, or whether, for machines of 
such large dimensions and heavy weight, it has been found 
mnrr suitable, it is not possible to say. 

As already mentioned, the material used in the construc- 
tion is, with very few exceptions, steel, practically the 
only parts made of wood being the ribs of the main planes. 



The main spars are in the form of steel tubes, which ii 
rattier surprising in view of the fact that about the worst 
use to put a circular or tubular section is to employ it as 
a beam laterally loaded, since much of the material of 
such a section will be situated at or near the neutral axis, 
where it is adding weight without contributing greatly 
towards the strength. Possibly the tube has been chosen, 
in this instance, for reasons connected with the manufac- 
ture rather than from considerations of structural suit- 
ability. The method of attaching the root of the main 
spar to the center section of the top plane is shown in 
one of the sketches. The short length joining the center 
section spar and root of wing appears to be turned from 
the solid, hollowed out at one end to receive the center 
section spar, and having machined on the other a forked 
end to receive the root of the main spar. The strut socket. 
which resembles those usually found on German machines, 
is attached to it by welding. 

Like the rest of the machine, the fuselage of the A. K. (i. 
bomber is built up of steel tubes, this material being used 
for longerons as well as for struts and cross members. 
These are connected by welding and the joints are stiff- 
ened and anchorage provided for the cross bracing wires 
by triangular pieces of sheet steel welded to longerons 
and struts. 

With regard to the accommodation for the occupants, 
this is divided into three divisions. In the front cockpit 
at the extreme nose of the body is a seat for tin- 
bomber, who views the ground below and obtains his sights 
through a circular opening in the floor. On his right the 
bomber has a rack holding bombs; these are presumably 
not of a very heavy caliber. Under the center of tin- 
body there is another bomb rack carrying the heavier pro- 
jectiles. Near the inner ends of the lower plane there 
are fittings for an additional supply of bombs. The ma- 
jority of the bombs, however, arc not, so far as it is pos- 
sible to ascertain, carried under the body and wings, but 
inside the body. 



80 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



The Curtiss Model 18-B Biplane 



After the successful trials of the Curtiss Model 1 8-T tri- 
plane, the two-seater 18-B biplane was brought out by 
Curtiss Engineering Corporation. The biplane is built 
around the same fuselage and power plant as the triplane, 
but having a lesser overall height the gunner has a wider 
area of fire. 

The housing of the engine is particularly neat ; it is en- 
tirely encased with the exception of the exhaust stacks, 
which are streamlined. The removable cowling around 
the engine makes the power plant accessible for adjust- 
ments and repairs. 

As in the triplane, all interplane cables are of true 
streamline. Where cables cross, they are clamped to- 
gether by streamlined blocks. 

Another peculiarity of this machine is the employment 
of ailerons on the lower plane only. These ailerons are 
operated by steel tubes running through the lower plane 
and directly connected to the pilot's control stick. This 
principle entirely eliminates all outside control cables and 
rigging. 

Rudder and elevators are operated by levers enclosed in 
the fuselgae termination thereby doing away with all out- 
side control cables. There are no external braces for the 
stabilizer or fin. 

General Dimensions 

Span, upper plane 37 ft. 5% in. 

Span, lawer plane 37 ft. 5% in. 

Length overall 23 ft. 4 in. 

Height overall 8 ft. lOy., in. 

Chord, upper plane ft. 54 in. 

Chord, lower plane ft. 48 in. 

Stagger ft. 16 9/16 in. 

Gaps, between planes 5 ft. in. 

Weights 

Pounds 

Weight, fully loaded 3,001 

Useful load 1,013 

Performances 
(Altitude) 

Feet 

Service ceiling 23,000 

Maximum ceiling 23,7.50 

Climb in 10 minutes 12,500 

Climb in 10 minutes (light flying load) 16,000 

(Speed) 

Highspeed (m.p.h.).. lfiO.5 158.5 157.5 155 152 

Altitude Sea SflOO 10,000 20,000 15,000 

level feet feet feet feet 

Low speed (m.p.h.) . . 59 68.2 73.6 79.8 86 
Kconomical Speed 

(m.p.h.) 80 85 92 100 118 

(Climb) 
Kate of climl, 

(ft. per minute) ...2390 1690 1040 580 210 
Time of climb 

(minutes) 2.5 6.3 12.9 27 

(Endurance) 

Miles Hours 

High speed (sea level) 283 1.75 

Economical speed (sea level) 536 6.7 

Main Planes 

Planes are in flat span. There is no dihedral nor 
sweep-back. 



Main planes are in five sections. Center section over 
the body 30 in. wide. Outer section 17 ft. 5% in. in 
span. Overall span 37 ft. 5% in- Lower plane in two 
sections at either side of the body, each 17 ft. 5% in. span. 

As indicated on the accompanying line drawing, the ribs 
are spaced about 6 in. apart. Instead of the usual two 
main wing beams, the Model 18-B employs five main wing 
beams, the idea being to more evenly distribute the loading 
on them. 

The chord of the upper plane is 54 in. Forward main 
wing beam located 9 in. from leading edge. Wing beam 
over the rear fuselage and interplane struts 2 ft. 9 in. 
from leading edge. 

Chord of lower plane 48 in. Forward main wing beam 
9 in. from leading edge. From this the other main wing 
beam members are spaced 75/16 in. apart. 

Ailerons on the lower plane have a very high aspect 
ratio, being 13 ft. 5 1/16 in. in length and 10% in- wide. 

Struts over the fuselage are spaced 30 in. apart. From 
these the intermediate interplane struts are centered 6 ft. 
ll/> in. From intermediate struts, outer struts are cen- 
tered 7 ft. 81/2 in. This leaves an overhang of 43% in. 

Fuselage 

The fuselage is of monocoque construction, finely stream 
lined. Overall length, 21 feet. 

Pilot's cockpit is below the trailing edge of upper plane. 
Aft of the pilot, the gunner's compartment is arranged so 
that the gunner has a wide range of fire for the two Lewis 
machine guns, one of which is located on a rotatable Scarff 
ring surrounding the cockpit, and one which fires through 
an opening in the under side of the fuselage. 

Landing Gear 

The track of the landing gear is 59 5 /s in. Wheels 26 in. 
in diameter. The axle is located 44 1 / 4 in. from the nose 
of the fuselage, and 491/2 in. below the center line of en- 
gine. With the machine in flying position, the center of 
gravity of machine occurs at a point 16.6 in. behind the 
axle of landing gear. 

When at rest on the ground, a straight line from the 
landing wheels to the tall skid makes an angle of 1 1 de- 
grees 15 minutes with the center line of thrust. 
Tail Group 

The triangular fin is 3 ft. in length and 3 ft. 6 in, in 
overall height. Rudder, 46 in. in overall height and 31 
11/16 in. in width. The stabilizer is divided at either side 
of fuselage. Maximum deptli at the body, 2 ft. 5 in. 
Maximum span overall, 10 ft. 10l/ 2 in. Elevators are 
18% in. in width. 

Engine Group 

The engine is a Curtiss Model K-12 engine. 

Two Duplex type carburetors are used. They are lo- 
cated between groups of cylinders. Carburetors are sup- 
plied with an auxiliary altitude hand-controlled air valve 
and also with non-back-firing screen. 

The propeller is 9 ft. in. in diameter. In flying posi- 
tion, the tips of the propeller clear the ground by 81/2 in. 
When the machine is at rest there is a clearance of 17 1 /.. in. 
between the propeller tips and the ground. 



Ml -LTI-MOTOKKI) AEROPLANE 



81 



The Curtis* " Oriole " Biplane 

Tlu- "Oriole" was brought out to (ill tin- need of a Main Planet 

ni.-ii liiin- tin- sol,- |iur|iosf of which is tin- carrying ot pas |>t for tin ccnti-r section, ninill plnnrs are made up 

si liters in i sit', and comfortable manner. A door is pru of sections similar in ->/< .-iiui ar..-i Main wing sections 

v iiled tin tin- left Mtlr of tin- hotly i indica'.i il by dashed are set at a I 1 - tli v r ' ' ililnilr.il jingle, 
lint- on the drawiiii: i, so the compartment is easy to get into. Portions of the ni.-nn planes jirt- flit away next to the 

Tin- i;i neral speeitientiiins an-: bodx anil null .- section to pt-rinit wide \ision rnngt- for 

General Dimensions passengers ami pilot. 

S '""' '"'>"" '','"" ' Fuselage and Landing Gear 

Snail, lower plain- ' ". III. 

( 'lior.1. Loth plaii.-s 5 ft. o iii. ' llr ntOfft is v!* ft. X in. ill overall length. IU sec- 

L.-iiL'tli. overall .'A ft. il in. tion is oval, .S ft. ' in. liy X ft. H in. With tin iis-iin . tin 

H.-i-lit, OMT.-I|| ft. A in. fusel.-mr ialiis :i.'-, H>. 

Provision is made fur carrying two passengers seated 

Weights ^ ,,,), |, v ,|,1,. i,, (). forarcl nn-kpit Jinil the pilot in the 

r. fnlh I... -I , """ aft '' r '''^l 1 ''- C "" lr " ls l<K - nt '-' 1 ' P' 1 " 1 '- "'^l" 1 ""*? 

,-! |, m ,| ' ;i,; Coiiipartnifiits are upholstereil in leather. Large wind 

N.I uei^ht. inrlinlin^ water M-'l s|,n Ills provide protection from the winil. 

Useful Load Because of the deep lio<ly. short struts Jin- list il on the 

!'"'> landing chassis. \\'hei-ls art- -'(! in. x M in., .spaced ft. 

Pd (43 *) tin. apart. 

Oil (I (rals) :W 

.,.| ()| l (jo \\ ing tips nn- provided with cnne bow skids, In low the 

Passt-inrrr or .itlirr |...ul 3iO outer wing struts. 

Speed Tail Group 

M.l'.ll. M.l'.ll. M.l'.ll. Stahiliascr It) ft. 1 .1 in. in span. >' ft. (i in. in mnximum 

'"' ft - width. The stahili/.er is tlivitletl nnd symmetrically dis- 

M.IMMIIIIII speed - 8S.O -" " * 

Mniit.i.im sp,.,.,| 475 5I.H 56.0 P os 1 *" side of the body. 

.niit-al spt-ftl 60.0 64.5 71.0 Klev.-itors. I ft. (5 in. wide. 

Climb ' '" '-' ft - <; in ' w ' <ir ; ""l :l fl - :1 '" "igh. Rudder sur- 

ffft face is all disposed above the fuselage, as the body- termi 

(Timl. (full load) in 10 minut,- 2,+75 natcs jn a strean ,i ine f orm . Rudder I ft. in. high. -' ft. 

It. id of i-linih. per iniiuite 400 fi .^ ^.jjp 

Endurance Engine 

Mil ft Hour* 

\t lii-h sn,',.ii 365 43 A Curtiss OX-5 Engine is used. This is an eight 

At iTonnmiral spee<l 393 6J cylinder " V " type, four stroke cycle engine. 




Side view of the Curtiss " Hornet," model 18-B, two-seater biplane. It has a speed of 163 m.p.h. and climbs 16,000 feet in 10 min- 
utes, with light flying load 



CHAPTER III 
SINGLE MOTORED AEROPLANES 




The Aeromarine Training Tractor 



The Aeromarine Training Tractor 



This machine is well suited for training purposes. 

General Dimensions 
Span, upper plane ........................ 37 ft in 

Span, lower plane ............................... 33 ft! in.' 

........................................... 6 ft. Sin. 



6 ft. 6 in. 
Length over all .................................. 25 ft. 6 in. 

V i eight, empty .................................. 1>300 , bs 

Useful load ..................................... 700 lbs 

Motor, Aeromarine .......... 100 h p 

Speed Range ...................... ...'.'.'.'.'.' .'.'.' .'78^2 m.p.h. 



I limb in 10 minutes 



3)500 



Planes 



In form, the wings are designed after the R. A. F. 6 
pattern. Leading edge of planes are covered with thin 
veneer to maintain the correct front curvature. 

Ribs are of lightened section, spaced about 12 inches 
apart. The rib webs are reinforced between lightening 
holes to protect against shear. 

Struts are hollowed to lightness as much as practical. 

In the internal wing bracing, separate wooden struts 
and not wing ribs carry the drag of the wings. 

Fuselage 

Longerons are of large section, lightened at points where 
the strength would not be impaired. Consideration has 
been given to the rough usage to which the bodies of 
school machines are subjected, and all wires, turnbuckles 
and fittings are designed accordingly. 

The fuselage is 22 ft. 6 in. in length, 2 ft. 6 in in its 
maximum width, and 3 ft. 6 in. in over all depth at the 

82 



pilot's cockpit. Both cockpits are arranged with a full 
complement of instruments. 

Tail Group 

The stabilizer is divided and mounted on either side 
of the body. In design it is of the double cambered type. 
The sections of the stabilizer are quickly detachable from 
the fuselage. 

Elevator planes are each attached to the stabilizer by 
four hinges. From tip to tip the elevator planes meas- 
ure 10 ft. 9 in. across; width, 2 ft. 5 in. 

The rudder is of the balanced type and of streamline 
section. The frame is formed of steel tubing. From the 
bottom of fuselage the rudder reaches a maximum height 
of 4 ft. in. The balanced portion extends 1 ft. 3 in. 
forward of the rudder post, and the main portion 2 ft. 1 1 
in. to the rear of pivot. 

Landing Chassis 

Axles are li/., in. diameter. Between the wheels the 
tube is 134 i n . in diameter. Walls of the axle in the hubs 
are 8/16 in. Hubs have bronze bushings. 
Motor Group 

Provision is made for the installation of the new Aero- 
marine 8-cylinder 100 h.p. motor. The gear ratio is 7 
to 4, turning an 8 ft. 4 in. Paragon propeller with a 6 ft. 
pitch at 1400 r.p.m. The motor is 4-cycle, with a bore 
of Sy 2 in. and a 5% in. stroke. 

Delco starter and ignition are provided and built in as 
an essential part of the motor. 





THE BELLANCA 

35 HP ANZANI 

LIGHT 



of f.t 



3 4 s e 



McLvMUb 



83 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Bellanca Biplane, .showing the neat appearance of the warping wings and streamline Locly 

The Bellanca Biplane 



The light passenger-carrying Bellanca biplane has been 
designed to answer the requisites of quick get away, fast 
climb, and high speed, and to have at the same time light 
weight, the ability to glide at a flat angle, and low flying 
speed to insure a great degree of safety in landing. To 
these qualities are added the item of moderate cost and 
ease of maintenance, high-grade construction and the pos- 
sibility of rapidly assembling and dissembling. 

The inventor had in mind the idea of presenting a ma- 
chine which would be of universal use for popular flying 
as well as for training. Careful attention was given to 
all details as dictated by the latest research and accepted 
good practice. That such things have been attained the 
demonstrations of its performances seem to bear out. 

On his first flight the pilot released the controls when 
an altitude of 1000 feet was reached. Perfect stability 
and high climb were observed. The throttle was full open. 
Without touching the controls, the throttle was retarded to 
diminish the power about 50 per cent, and the machine 
proceeded in straight horizontal flight. With the engine 
shut off the machine quietly disposed itself to a flat glide. 

Other tests of the machine's speed show that with full 
power, it is capable of 85 m.p.h., and by throttling the 
engine the speed can be reduced to 34 m.p.h. The value 
of this performance will be better realized when it is un- 
derstood that the Bleriot and Deperdussin monoplanes of 
similar horse power have a speed range of 40 to 46 and 
40 to 48 m.p.h., respectively. Favorable comparison will 
also be found with a number of modern machines, both 
European and American, with 100 h.p. or more, which 
make an average speed of 70 to 80 m.p.h. 

In climb tests the Bellanca biplane ascended to 3300 
feet in 10 minutes and 4600 feet in 14 minutes, with the 
engine throttled down to 1080 r.p.m., equal to 18 h.p. 

With the engine turning at 1080 r.p.m. the machine 
made a speed of 691/2 m.p.h. in three consecutive half- 
mile flights at a height of 15 feet from the ground. The 
speed mentioned was the average for the three flights. 



W T ith the engine increased to 1200 r.p.m., equal to 24 h.p., 
the climb of the machine increased to 530 feet per minute 
and the horizontal speed was 76 m.p.m. The climb was 
measured by means of a barograph and aneroid. 

In testing the gliding quality, the pilot began a glide 
from an altitude of 4600 feet at a distance of about ten 
miles from the starting point. With the engine shut off 
the field was reached and passed, and it was necessary 
to turn back and glide against the wind toward the field, 
adding two miles to the distance traversed. In this 
manoeuver a time of 8 minutes and 5 seconds elapsed be- 
fore the ground was touched. In this glide the machine 
was favored by a wind of 6 to 7 m.p.h. The incidence 
angle indicator showed that the machine was gliding at 
an angle of 5 degrees, which is equal to a ratio of 1 to 
11.5. 

The above test shows that in case of a forced landing 
from an altitude of 4600 feet, the pilot will have ample 
time to select a landing place within a diameter of 24 
miles. 

General Description 

Best selected white ash is used for the principal parts 
of wings, fuselage, landing gear, etc. 

Brazing and welding have been eliminated wherever 
possible. Care has been observed to avoid the piercing 
of longerons and other vital members. 

Safety Factor 

The factor of safety of lift stresses on the beams of 
upper and lower wings is 16, and the factor of drift 
stresses is 14. In the body and landing gear the safety 
factor of the weakest point is 12. 

Field tests have shown a high safety factor under 
difficult conditions. Even in snow 14 inches deep, the 
machine never met with difficulty in leaving the ground 
nor in landing. In diving and even in tail spinning tests, 
the machine was quick to recover itself, confirming the 
strength of sustaining surfaces. 



SIM, 1. 1. MOTOKK1) AKKOI'L. \.\KS 



n 



Assembling Facility 

In actual tests, tin- machine was dissembled in 1 /, min- 
nt.-s and re.-issciiihlcd ready to fly in -JU ininiitrs. This 
id in is expiditcd liy tin- employment of a -p. vial turn- 
bucklc, which can lie loosed and detached without losing 

tin- adjustment of tension, so that a simple \emeiit 

restores the attacliiilrnt of the cable with its original 
adjustment. 

General Specifications 

Span, upper pl.-inr .'(i ft. II in. 

Span, lower plain- ft. 6 in. 

Chord, upper plain- I ft. (> in. 

Chord, lower plane ..... .' It. t In. 

I ... I 40 sq. ft. 

th overall 17 ft. 7 in. 

Weight, iiini-hini- empty 400 Ills. 

I ''! l""l -' ,.373 II.-. 



Performances 



Maximum Speed. 



Minimum Speed 



IM 

N h.p.... 
[ 18 h.p 



in ft 

per hour) 
83 
76 
70 
34 



M ixiiiiiim Cliint.iiiir Spreil 



per min.) 

fS5 h.p... . 830 
I j^ i W 

[18 h.p ....... 330 

Cli.linir \nglc ...................................... 1 to 11.3 

Min. h.p. required for hori/. mtal Hight ...................... 6 

Main Planes 

The dynamical stability of the planes is almost the same 
a- tin- Kitl'el :i-.'. It is most suited to high speed because 
of it- v.r\ small drift at small angles of incidence, and 
l.eeau.sc of the structural advantages afforded by the sec- 
tion. 

Spars are of ash, having a safety factor of 1 t. 

Struts between planes arc of streamline section of con- 
stant depth for two-thirds their length. Ends taper to 
the strut fittings. 

Controls 

Lateral and longitudinal balance is operated by stick 
control. The rudder is balanced; it is operated by tin- 
foot bar. 

Lateral control is obtained by warping the wings, and 
it- effect is so immediate as to require but a slight move- 
ment of the stick. 



Fuselage 

The fuselage is of good streamline form. Ita wooden 

I r mie i- of IM.X girder construction, braced hv cables from 
the pilot's eoekpit forward and with wire from the sam. 
cockpit rearward. The nose is co\ered with aluminium. 
a round door in on, side giving access to the engine. 
The reniamdi r i- covered with linen. do|M-d and varnislud. 
The front deck i- ..I veni.r. linen entered. The body 
tapers to a vertical strut edge at the rear, on which the 
rudder is hinged. No U.lts pass through the fuselage 
-pars, a simple ami light fitting making this possible. In 
front of the pilot is a dash, on which are found oil sights, 
clock, aneroid, inclinometer, and incidence angle indi- 
cator. 

Landing Gear 

The chassis i- of the ordinary V type, each V con 
sisting of two ash laminated streamline struts, joined to- 
gether by steel ami aluminium plates. Rubber shock ah 
sorbcrs bind the axle to the struts. 

Tail Group 

The empannage group is composed of a non-lifting fixed 
stabilizer, to which is fastened the elevator flaps. 

The attachment of the stabilizer is such that it is easily 
detached by removing four cotter pins. 

The rudder is of oval shape and is of sufficient area 
to insure complete control in handling the machine on 
the ground. 

Engine Group 

An air cooled .1 cylinder An/.ani Y type 35 h.p. is used. 
Its weight is 1*0 Ibs. Propeller 6 ft. 7 in. in diameter 
and 5 ft. 9 in. pitch. The engine is so attached as to 
form with the rest of the body a perfect streamline form 
with low head resistance. 

Only part of the cylinders are exposed, which are effica- 
ciously cooled by such a flow of air as obtained by a speed 
of 85 m.p.h. 

To ascertain the complete cooling of the engine, re- 
peated and accurate tests were performed. The engine 
was first tested on the ground, and after five minutes' run- 
ning, it was already losing 15 |>er cent, of its initial h.p. 
This loss was increasing as the engine continued to work. 

On the contrary when the machine was flying, such 
power loss was almost completely eliminated, for after 
from 40 to 6<> minutes of flight, no over-heating was ob- 
served. 



The Dellnnca Biplane in flight 





CURTI55 

MODEL JN4-B 
MILITARY TRACTOR 



Scale of Feet 



-fe 



86 



SI\(;i.K MOTOHKI) .\KK01M..\.\KS 



K7 




'II,.- well known Curtiss .INI, cuuippcd will. ,, Hispaiio-Sui/.a motor. This type of |.| lin r was used extensively for training pur- 

POM-S. It was originally powered with a Curtis OX s cylinder motor. 



Curtiss Model JN-4D Tractor 



Due to tlic f.ut that tliis machine has been widely used 
for training .m.ttnrs both IHTC and abroad, the JN tvpr 
i- prok-il.lv the la-st known of all the Curtiss models. 

It is comparatively \i\i[ and for its useful load carry- 
ing rapacity, is very compact. 

General Dimensions 

'iii)r S|uin t'pper Plane .................. 43 ft. 7% in. 

in^r Spun Lower Plane .................. S3 ft. 11% in. 

Depth of Wing Chord ....................... 591^ | n . 

C.lp lietucell Wilier, ......................... 61% j n 

Stagger .................................... 16 in . 

Length of .Machine overall ................... .'7 ft. + in. 

Height of Machine overall ................... 9 ft. 10% in. 

AiiL'le of Ineiili-nee .......................... i degrees 

Dihedral Angle ............................. 1 ,|,.grec 

Swi-.-plm.-k .................................. decrees 

Wing Curve ................................. Kiffel y o . ,; 

Horizontal Stahiliier Anple of Incidence ____ degrees 

Areas 

ind's - fpper ..... ......................... 167.94 ^ f t . 

-I^'wrr ......................... 149. sq. ft. 

" s ( l'|'l'T) ........................... 35.3 sq. ft 

Horizontal Stahiliu-r ........................ 28.7 sq. ft. 

Verlieal Stahilizer .......................... 3.8 ,. ft. 

Klevators (each 11 (. ft.) ................... a sq. ft. 

Kiitlder ..................................... U sq. 

Total Supporting Surface .................... 352.56 

Loading (weight carried |-r sq. ft. of support- 

ing surface ) .............................. 6.04 M.S. 

|MdlOf (per It. H. P.) ..................... 23.65 Ibs. 

Weights 

Net Weight Machine K.inpty ............... 1^80 Ibs. 

CirosN \\'ci)rht Machine and Load ........... 3,13() ll.s. 

I'seful I^,a<l ................................ 550 n, s . 

Fuel ............................... 130 ll.s. 

Oil .................. 38 ll.s. 



I'ilot 165 Ibs. 

Passenger and other load 217 Ibs. 



ft. 
sq. 



ft. 



Total 540 Ibs. 



Performance 

Speed Maximum Horizontal Flight 75 miles per hour 
Speed Minimum Horizontal Flight *5 miles per hour 
Climbing Speed 3000 feet in 10 minutes 



Motor 

Model OX. H-Cylinder, Ve-, Four-Stroke Cycle. . Water cooled 

Horse Power (ruled) at I KM) H. P. M 90 

Weight per rated Morse Power 4.33 Ibs. 

Bon- and Stroke 4 In. x 5 in. 

Fuel Consumption Hour 9 gals. 

Fuel Tank Capacity 21 gajg. 

Oil Capacity Provided Crankcase 4 gals. 

Fuel Consumption per Brake Horse Power per 

Hour 0.60 Ibs. 

Oil Consumption per Brake Horse Power per 

Hour 0.030 Ibs. 

Propeller 

Material Wood 

Pitch according to requirements of performance. 
Diameter according to requirements of performance. 
Direction of Rotation (viewed from pilot's seat) Clockwise 

Details 

One Gasoline Tank located in fuselage. 

Tail Skid independent of Tail Post. 

Landing Gear Wheel, size 36-in. \ t in. 

Standard Equipment Tachometer, oil gauge, gasoline gauge. 

Maximum Range 
At economic speed, about 250 miles. 





DEHAVILLAND 4 

4OO HP LIBERTY 

RECONNAISSANCE PLANE 



Sclo y Feet 



88 



SIXGI.K MOTOHK1) A KKOI'I.A M. 




.ITU -motored I)t- I l.ivili.ind four, with l)oinl) racks filled for IxHuliing demonstration 



The De Havilland 4 Tractor Biplane 



The De Havill.ind I with the Liberty engine has been 
one of tin- successful associations with America's air pro- 
gram. For reconnaissance and bombing the British have 
i ill. I>. ilavillanil I- with a Sou h.j). Rolls-Royce en- 
gine, mid tin- adoption of tin- Liberty 12 has given the 
t iiitnl Stat.-s superior results in both performance and 
production. 

With slight modifications in its equipment, the De Havil- 
l.-inil t is used for reconnaissance, bomb dropping and 
tinhting. Complete night flying equipment is installed, 
consisting of .jrceii and red port and starboard electric 
lights near the ends of the lower plane, a rear white light 
on the deck just aft of the gunner's ring, and wing tip 
Han lights near the wing tip skids. 

Current for lighting and wireless is supplied by two 
generators attached to the inner sides of front landing 
gear struts. A camera is clamped to a padded rock on 
the interior of the body aft of the gunner's ring, where it 
i-. coineniently operated by the observer. Dual control 
is installed, and control stick is quickly detached and 
removed by pressing a spring catch when it is not neces- 
sary for the observer to take control. 

Hacks are provided for twelve bombs which are held 
in place horizontally under the lower planes, near the 
body. The release is accomplished from the pilot's cock- 
pit by means of bowden cable. A sighting arrangement 
is built into the body just behind the rudder bnr. 

Four machine guns are installed. Two fixed Browning 
guns are mounted on the cowling forward of the pilot, 
operated by the " C. C." automatic interrupter gear or 
the Nelson direct mechanism, which releases the trigger 
at each revolution of the engine crankshaft. Two mov- 
alile Lewis guns are carried on a rotatable scarfed ring 
surrounding the rear cockpit. 

A telescopic sight is provided for the two fixed forward 
guns and a ring and bead sight for the twin Lewis guns. 

Instruments carried are: Two gasoline pressure indi- 
cators, speed indicator, tachometer, altimeter, thermometer, 



clock, hand-pressure pump, inclinometer, map board, and 
compass. 

General Dimensions 

Put 

Span, upper plnnr 4.' t 

Spun, lower plane 4iJ3 

( 'liord, lK>th planes 4.*7 

Gap between planes 8.0 

Staffer li.6 

Lrnirth over all 29.7 

Height over all 10.84 

Areas 

Sijuart fftt 

t'pper plane 916 

Ix)wer plane 30i 

Ailerons (3 upper and 1 lower) 76 

Totiil wing area with ailerons 4il 

Stnliiliwr 33.7 

Elevator 833 

Fin 4.1 

Rudder U.4 

Weights, General 

Pound* 

Murhine empty 2,**0 

Ftn-1 and oil .' *4i 

Military load ** 

Total, machine loaded 3,7*0 

Kstiin.il.il n-cful load 1,300 

Weights, Machine Empty 

Pound* 

Engine * 

Kxhaust pipes 

Radiator and water 1 

Propeller 

Gasoline tanks 

Oil tank 

Engine accessories, leads etc. . . . 

Fuselage with cowl 3"** 

Tail plane, Incidence gear 

Body accessories, seats, etc 

l'nd"ercarri(re ' " 



90 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Front view of the De Havilland-4 with a 400 h.p. Liberty "12" Engine 



Tail skid 

Controls 

Wings . . 

Bracing 

Armament supports 



11 

21 

460 

68 

88 



Total 2,440 



Military Load 



Crew 


Pounds 
330 


Armament 


163 


Bombs and gears 


322 


Photographic outfit 


22 




11 






Total 


848 



Main Planes 

There is no sweepback, but upper and lower planes are 
attached to a center section and the body, respectively, at 
a dihedral angle of 174. 

Aspect ratio of both planes, 7.7. Angle of incidence, 
3. 

Fuselage 

Veneer is used for covering the fuselage from the ra- 
diator to the gunner's cockpit, and no diagonal bracing is 
therefore employed in this part. 

The rear end of the body is constructed in the usual 
girder fashion, and the longerons, of spruce, are spliced. 
Veneer is used underneath the tail plane for covering the 
body. 

Tail Plane 

Attachment of the tail plane is such that its inclination 
can be varied from the pilot's cockpit during flight. Its 
front edge is hinged and the rear end braced by wires at- 



tached to a vertical post in the fin. By means of a cable 
wrapped around a drum and worm at the lower end of the 
post the rear brace wires are raised or lowered, and the 
trailing edge of the stabilizer is correspondingly raised or 
lowered, permitting the setting to be adjustable within the 
limits of 2 + 5. 

Engine Group 

The engine is a twelve-cylinder Liberty which develops 
400 h.p. at 1,625 r.p.m. Bore and stroke 5 by 7 inches. 
Cylinders are set at a 45 V. 

Zenith carburetor and Delco ignition are used. 

Fuel consumption .54 }bs., and oil .03 Ibs. pr h.p. per 
hour. Fuel tanks are located at the center of gravity. 
Capacity 67.6 gallons. Oil tanks under pilot's seat have 
a capacity of 5.6 gallons. 

The radiator is provided with shutters operated from 
the pilot's cockpit, to cut off part of the cooling surface 
when flying at low temperature. 

Propeller, 8.6 ft. diameter and 10.7 ft. pitch. When 
at rest on the ground the propeller hub is 6 ft. in. above 
ground, and in flying position it is 5 ft. in. above ground. 



Performances Obtained by U. S. Army with the DeH-4 

Endurance at 6..300 ft., full throttle 2 hrs. 13 min. 

Endurance at 6,500 ft., half throttle 3 hrs. 3 min. 

Ceiling 19,500 ft. 

Climb to 10,000 ft 14 min. 

Speed at ground level 124.7 m.p.h. 

Speed at 6,500 ft 120 m.p.h. 

Speed at 10,000 ft 117 m.p.h. 

Speed at 15,000 ft 113 m.p.h. 

Weight, bare plane 2,391 Ibs. 

Weight, loaded 3,582 Ibs. 



K .MOTOKKl) AKMOI'1.. \\KS 




Th, MrilM, Vfchei. ,,,,n,,,,.r,ial I, ,,, VJM.J - equipped with two HolK-Km,-, :<7 5 h.p. ,,!,... Two 

.-kpit placeil high in II,.- MUM- <! thr i-Hhin li> a srtin K raparily f.r 10 
passengers in .s-pHrtc .inn rhiiir-. Knrl is rnrried for 
five hours; speed, 110 m.p.h. 



are rarrinl in Ihr 




The British Bristol Coup* biplane equipped with ^64 h.p. Rolls-Royce engine 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 





Line drawings of the D. H. 5 pursuit biplane 



SINGI.K MOTOHKI) A KI)1M.A\KS 




i.-mll,.ii.l ',. ,i,,,u,,,.. tl.r ,-,.,,,li;,r s t ,, Btri . r ,,f ,)- ,,,.,. . lrn , Ml ,,;,.,, f ; vt . s . Jli|ot widc rangr of vjs|(in 

The D. H. 5 Pursuit Biplane 

This in u liin. is a tractor biplan. with a single pair Chord, I.S7. 1 } m. 

of iiit<T|iI:nif struts mi each side and with the wings set Dihrdral, 17'.' 

:it .-i n. ptin il tgf r t .;;..', m . The principal dimen- Angh- of incidrn.-,-. upper wing, 2, amidwings, 2l/, at 

lions, etc., .in ,s foll,, tip . lower wing 2l/ /.o throughout. 

No .swcfpback. 

Wing spars of spruce and of I-section. 
' m - Rihs spaced 280 to 350 mm. apart. 




Dimensions in millimrters. Detail drawings of the D. H. 5 fuselage 



TKXTHOOK OF APPLIED AKKONAl'TIC ENGINEERING 




The IV Ha\illuml No. .>. Mils;!.' M-ator tighter 



The De Havilland No. 5 

Ordinary four-longitudinal typo, braced by cross wir- 
ing and strengthened in front, up to pilot's seat, and at 
rear near tail by ,S mm. plywood. Body faired to approx- 
imately circular section near front. 

The undercarriage is of V-type with solid streamlined 
wooden struts and a continuous axle. The tail plane is 
of one piece mounted at 1 incidence, without the cus- 
tomary incidence-change gear. 

The power plant consists of a 110 h.p. rotary Le Rhone, 
with main fuel tank for 100 lit. of gasoline and oil tank 
capacity of 21 lit. There is an emergency gravity fuel 
tank of 26 lit. capacity on upper starboard wing. The 



engine is fed from m.-iin tank by compressed air generated 
by small air pump. Total fuel supply for two hours' 
flight. 

The following instruments are mounted in the pilot 
cockpit: To right, two fuel supply pipes with stop cock-. 
and a change of gear for elevator control: on instrument 
board, tachometer, speedometer, altimeter, -.park switch, 
watch and compass; to left, fuel and oil throttles and a 
hand pump for the air. 

The weight of the machine is: Empty. U>1 kg., and 
fully loaded. 691 kg. Wing area is 20.1-1 MJ. m.. wing 
loading S-H kg. sq. m. and power loading ."'.;*, > kg. h.p. 




The Thomas-Morse S-V K Single 
Seater Advanced Training Scout, 
which makes a spwd of 11.' m.p.h. 
with an SO h.p. Le Rhone engine 



SIM. I I. MOTUKK1) AKKOl'l \\l - 







The Dayton- Wright D-4K. It has two uphol-tcrrd scats, huilt-in mahogany vanity ami lunrh boxrs, and x-vel platr mirror-;. It 
i<l pilot. It U equipped with a Lihrrtv Twelve. The machine has a maximum speed of ir. mil. ~ |.rr 



holds two passengers anil |>il<it. It is equipped 
hour and minimum of 53. The climb is about 10,000 feet in 10 minutes and the 
; are similar to the DH-i 



radius is four hours. The dimen- 



96 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Dayton-Wright " Messenger" Biplane. It has a wing spread of 18 feet 5 inches, weighs 4T(i pounds net, 636 gross, has a max 
mum speed of 78 miles per hour, minimum 40 miles, and is equipped with a 37 horsepower 

The T-4 Messenger 



The " Messenger " was designed as a war machine, but 
after being modified in small details it makes an ideal ma- 
chine for commercial and sporting purposes. As a war 
machine its use was to have been in carrying messages 
from the front lines to headquarters, and in general liaison 
work. 

The machine is exceptionally light, and easy to fly, mak- 
ing it possible to make landings in places that have been 
heretofore unaccessible. Very rigid flying tests have been 
made. 

The fuselage has absolutely no metal fittings nor tie 
rods of any sort, strips of veneer being used exclusively 
for the bracing. 

As an example of its strength, the fuselage was sup- 
ported at either end while 12 men stood at the center. 

The machine comes within the means of the average 
sportsman, for its cost is said to be not much over $2000. 

General Specifications 
Span, upper plane 19 ft. 3 in. 

STHL'CTUKAI, DETAILS OF THE D 



9 in. 
17 ft. 6 in. 
6 ft. 1 in. 
6? 
3 
i/ 2 in. 



Span, lower plane ' 9 

Chord, both planes :i *'* : Wu '" 

Area, upper plane ^ sc l- " 

Area, lower plane j6 S 1- ^- 

Gap 3 ft. 8>/ ? in. 

Stagger 

Length 

Height 

Angle of incidence 

Dihedral of lower plane 

Stabilizer incidence 

Weight unloaded 4T(i 11)s 

Weight loaded 

Horizontal maximum speed 85 m.p.h. 

Landing speed :?T m.p.h. 

Climb in 10 minutes 

Engine, air-cooled De Palma :!T "-P- 

The engine is a 4-cylinder air-cooled " V " type manu- 
factured by the De Palma Engine Company of Detroit. 
Its weight is 3.7 Ibs. per h.p. The engine consumes 4 
gallons of gasoline per hour and tank has a capacity o) 
12 gallons. Oil is carried in the crankcase. 

AYTOX-WRIGHT T-4 "MESSENGER" 








I Lower right wing strut socket, showing pulley for aileron cable fitted into the leading edge of the wing. 2 The strip veneer 
used for cross bracing on the interior of the fuselage. 3 Attachment of upper wing section to the center section. 4 Ele- 
vator control lever. 5 Landing chassis fitting snowing the streamline aluminum casing for the shock absorber cord. 





BEQCKMAN5 

IOO HP G.V CNOMt 

SPEED SCOUT 



3cU of F.,l 



McLuhim 



98 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Side view of the Berckmans Single Sealer, 
equipped with a Gnome motor of 
100 h.p. 



In a great number of points, the little single-seater, 
designed by Maurice Berckmans, shows a marked advance 
in scout-building which has resulted in some perform- 
ances worthy of note. This plane has ascended to 22,000 
feet and returned to the eartli in twenty-seven minutes. 
Its normal climb is 1100 feet per minute. These figures 
were verified by an altimeter (indicating barometer) and 
two recording barographs. 

Quick climbing ability is but one of the inherent features 
of its design. The streamline monocoque body, the reduc- 
tion of exposed parts and the light total weight have as- 
sisted in the achievement of high speed. A judicious dis- 
tribution of weights and areas, bringing the centers of 
area, thrust, gravity and resistance in advantageous posi- 
tions, has made the machine easy to control and prompt 
and precise in response to control movements. These at- 
tributes, together with its neat details and finish, make 
this scout one of the fine American machines of this 
type. 



General Specifications 

Span, upper plane ' 26 ft. in. 

Span, lower plane 19 ft. in. 

Chord, both planes 4 ft. 11 in. 

Gap 5 ft. 3 in. 

Stagger 17 

Length of machine overall 18 ft. in. 

Height of machine overall 8 ft. 9 in. 

Net Weight machine empty 820 Ibs. 

Gross weight machine and load 1,190 Ibs. 

Useful load 370 Ibs. 

Engine, G. V. Gnome 100 h.p. 

Speed range 115-54 m.p.h. 

Climbing speed 1,100 ft. per -min. 

Gliding angle 8 to 1 

Radius of action 2% hrs. 

Main Planes 

The upper plane is in two sections with a 1 dihedral; 
lower plane in two 9 ft. 6 in. sections with a 2 dihedral. 
Angle of incidence of both upper and lower planes, 2.1; 
1.5 at tips. Stagger, 17, amounting to 16 inches. No 
sweepback. 

Area of the upper plane, 10.6 sq. ft.; lower plane, 77.9 
sq. ft. Total supporting surface, 184.S sq. ft. Loading, 



The Berckmans Speed Scout 

or weight carried per square foot of supporting surface, 
6.4 pounds. 

Wing curve, Eiffel No. 32. Ribs have I/., in. by 8/16 in. 
spruce battens and veneer webs. Veneer is with 3-ply 
birch-gum-birch, each lamination 1/16 in. thick. Ribs 
spaced along the wing 10 in. apart. 

Leading edge and the forward main wing beam are of 
spruce, and the rear beam of ash (the ash being necessary 
because of the relatively narrow depth of the Eiffel wing 
section at the rear spar). The trailing edge of 20 gage 
aluminum tubing with an outside diameter of % in. 

Ailerons on the upper plane only, 4 ft. 10 in. in span 
and 1 ft. 11 in. deep. The half-round leading edge is set 
into a curved recess in the rear wing beam, leaving no 
opening between these surfaces. 

Interplane struts are of spruce, hollowed for lightness. 
The halves are glued together with fiber crossed (for 
avoiding warping) and bound in three places to keep them 
firmly in place. Maximum width, 1^4 i n -> maximum 
depth (at the center), 4 in., tapering to 1% in. at the 
ends. The front edge is nearly straight and the rear 
curved in a pronounced gradual taper. 

Wiring between the planes is with flexible stranded 
cable; flying wires doubled and bound together to lessen 
resistance. The compensating control cable, from one 
aileron to the other, is run concealed in the upper plane. 
Inspection doors are located above the pulleys, where the 
cable ends emerge and run to the aileron king-posts. 



Body 

The fuselage is of the monocoque type, with a finely 
tapered streamline form. Its section at all points is per- 
fectly circular; at the forward end it is 3 ft. in. in 
diameter. It is built up of 3-ply spruce, except the por- 
tion from the pilot's seat to the engine, which is 4-ply. 
Laminations are 1/16 in. thick, with coarse 1/16 in. 
mesh fabric interposed to keep the glue from shearing. 

A headrest and streamline former is built onto the fuse- 
lage top aft of the cockpit. 

At the points where landing-gear struts and interplane 
flying cables are attached, the body is braced with rings 



SlN(;i.K MOTOKKI) AKUOl'I.AM.s 



M 



of 1/1(5 in. thick I' chaniK 1 steel, meted to tin- int.-rior 
wnll. 

MI. l control is installed: the stick for loBgftndiaa] nnti 

1-iteral inn\ i MK -iits. :iiul tlic foot -li.-ir fur ilircrtinn. 

Tail Group 

I.ijj!. 1 - 1 tubing is used in tin empen- 

nage construction. 

Tlic tixed tail plane is srt at a neutral anijlc. It is in 
two halves, attached to cither si<l<- of tin- lnly. Overall 
sjiaii. It. '.' in. : maximum depth. I ft. l in. ; ari-a. s -i\. ft. 

Tail Mips have a span nt 7 ft. ! ill. and a depth of 1 ft. 
! in.; ana. !'..' M|. ft. They art n . i ssed into tin- tail 
plain- so as to leave no spai-i- between tin- surfaces. 

Tin triangular vi -rtiral tin is I It. !i in. long and 1 ft. 
:i in. high. Area. _'.." sij. ft. 

Tin- ruddrr is of tin- halali.-cd type, with tin- balancing 
portion projecting forward under tin- body. It is ri-ri-ssi-d 
into tin- tin and liodv in the same manner as the Haps and 
tail. Maximum height. .; ft. :! in.; deptli re:irw ard of the 
ruddt r post. I ft. II in.; lialaneed portion. 7 in. forward 
of the rudder post. Hudder area, 7.5 s<\. ft. 

Landing Gear 

(.! it simplicity is seen in the lauding elmssis construc- 
tion. It riiiisjstt of a pair of '^fi in. by 3 in. Acki-rman 
spring wheels attached to a 1 ' _ ill. diameter 3 1(5 in. wall 
tulx axli -. Wheel tread, 5 ft. 3 in. 

Chassis memlers are I 1 , in. diameter 14 gage steel tube, 
streamlined with spruce fairing strips. Cross-wiring of 
hea\ \ llexilde cahlf. 

Tin- tail skid is mounted on a steel tube tripod, and 
.sprung with rubber shock-absorber elastic cord. 

Power Group 

Tin- engine is a rotary it-cylinder General Vehicle Com- 
pany's nionosoupape (uiomc. Bore, 110 mm.; stroke, 150 
mm. Rated h.p.. 100 at 1200 r.p.m. Weight, including 
vapori/.er and ignition, 272 Ibs. Fuel Consumption, l"i 
gallons per hour. 

To assure a good supply of rich air to the vaporizer 
when tin- machine is banking or spiralling, and a vacuum 
liable to occur on one side of the body, two intake ducts 
are provided, one at either side of the body. 




Det.nl view of the Brrrkmans Scout, frivinfr nn idea of tin- 
chassis 



The propeller is 8 ft. 4 in. diameter with an 8 ft. 9 in. 
pitch. 

The cowl surrounding the engine is of 1/16 in. alumi- 
num, reinforced with I. section aluminum .-mule In .mi. An 
opening in the side of the cowl is made for the exhaust 
of the engine, and an opening at the bottom for cooling 
the cylinders and to facilitate removal. 

Fuel is carried at either side of the fuselage interior in 
two Id-gallon tanks, running from the engine bulkhead 
to the rear of the cockpit and following the contour of the 
body. A 7-gallon oil tank is located at the top of the 
fuselage interior, just forward of the instrument board. 
The fuel is sufficient for a flight of v! 1 - hours. 




The Rrrckmans Scout It is equipped with a 100 h.p. General Vehicle Co.'s Gnome engine. 




The Christmas " Bullet " strutless and wireless biplane which makes a speed of 170 miles an hour with a 6 cylinder Liberty Motor 




Details of the fuselage and tail group of the Christmas " Bullet " strutless scout biplane 




Front view of the Christmas " Bullet," showing the absence of struts and bracing wires 

100 



Sl.\(;i,K MOTOKKl) AKKOIM.ANKS 



101 




I h, Christum., " HulU-t," in tli-1,1 at Mineola. I.. I. 



The Christmas Strutless Biplane 

> rnl ;ittrui|>ts have lit en made for years by experi- 
menters to perfect .'in aeroplane with flexible in^s. or 
following closely tlic tli -\iliility of tin- wings of a bird. 
The biplane designed li\ Dr. \V. \\' . Christinas ap|)<-ars to 
II.'IM- met with Miiich success in tin- structure mentioned, 
and liis tlu-orics of Hexing wings h.-i\e shown more prac- 
ticability than most rigid-wing :idln rents were apt to bc- 

lic\e possible. 

A most radical departiin- from what has heretofore been 
believed to lie incessarx practice is the entire elimination 
of struts, cable*, and wires in the bracing of the wings, 
as well is tin absence of wiring ill the internal structure 
of the wings. The wing curve is one developed by Dr. 
Christmas, and is of fairly deep section between the main 
wing beams, but tapering oil' sharply aft of the rear beam, 
anil merging into a Hat. thin, flexible, trailing edge. The 
cH'cct of the section is to maintain a high angle of inci- 
is til-- machine is traveling at low speed, and a 
lnyli angle as the machine gathers speed, flattening out 
the wing and presenting very little resistance. 

I'ppcr and lower wings have the same aspect ratio. 
I pp. r wing has a thickness of 5 inches. Patents are 
pending on the wing construction, and full details cannot 
now be gixcn of these features. 

With the wing section used. Dr. Christmas has sue 
< < ded in obtaining a 7- per cent, lift on the upper wing, 
a higher vacuum than found on any other section. Wings 

set at an incidence of .S'.j degrees. 

\- the wings are not braced transversely, flexibility is 

also obtained in that direction. I'litl's of wind, or sudden 

changes of direction, do not sharply afTeet the machine's 

>r the shock is transmitted only after being 

ly alisorlx-d by the resiliency of the wings. It 

would seem that such construction would result in a low 

factor of safety, but the designer claims a safety factor 

'.ii throughout. 

When at rest on the ground, the wing droops in a nega- 

tixe dihedral of - - 7 degrees. In flight the wing tips 

i range of flexibility of 3 feet; that is, the wings 



can assume positixe or innatix. dihedral measuring 18 
inches from the hori/.ontal in cither direction. 

It has I..,,, demonstrated Hint the wings carry a load 
O greater than me. ssjrx to sustain the machine in Hight. 
nd this load i> carried nuardhss ,,| wind pull's or extri 
-trains due to increased wind pressure above or In-low 
lh wmn. 

I'he principal specifications of the Christmas "Bullet" 
i"i!ow s 

<! .in. II|I|XT plan.- .1 |n. 

.-span, lower plain- U ft. In. 

< liord, II|>|MT plane i ft. (I in. 

Chord, lower plain- .' ft. li in 

\n-a, upper plan.- 140 M]. ft. 

\re.i. lower plnnr 30 st\. ft. 

length overall .'1 ft II In. 

\\i-itrlit. in.u-liiiM- einptx M.tl Ids. 

Weiirht. fully lonilcd ." :.loo llw. 

Miiiiiiiiini s|M-etl iO-60 m.ji.li. 

M ixiiinim speed 174 tn.pji. 

Cruising radius iiO milr^ 

Oiling :u,7oo f|. 

A Liberty " (! " is used, giving 18.') h.p. at I KID r.p.m. : 
the machine attains I7<l miles at three -quarter throttle. 
The weight fully loaded is with 50 gallons of gasoline and 
5 gallons of oil, sufficient for a sustained flight of three 
hours. 

The " Hullet " was originally designed as a single sealer 
tighter. The pilot has an unobstructed range of vision, 
as his eyes are at the level of the upper plane and the 
lower plain- has such a narrow chord that it offers but 
\cry little obstruction to vision. Although military in . 
sity docs not now demand the adoption of the machine as 
a tighter, it lends itself admirably to the needs of civilian 
uses. The planes are readily detachable and are easily 
set up. as there are no wires to align. When the planes 
are removed, they can be stnppcd alongside of the fuse- 
lage and the machine then takes up only about one-fifth 
of the room ordinarily required for storage. The machine 
can be rigged up ready for flight in 15 minutes. 

All the controls are exceptionally easy in their opera- 
tion. The tail is flexible, and its efficiency is illustrated 
by the fact that a 1 inch deflection causes a controlling 
moment equal to that produced by a rigid flap movement 
of 1 inches. 

The two main tail beams are 1 ' |. inches by I :t ( inches 
laminated spruce. A horizontal V section spruce leading 
.Li is used. The battens arc air-seasoned white ash. 

Aekerman spring wheels arc used, which cut down re- 
sistance and do away with the usual rubber shock absorber 
cord. 

The principle of radiation in original. Besides the M"-. 
radiator of the " Livingston " ty|>e, copper mesh screens 
cover in the sides and top of the fuselage, forward of tin- 
wings, and this surface has proven adequate for the Lib- 
erty " (i." Much of the radiation is thereby effected by- 
skin friction rather than by dead head resistance. 

The propeller has a 10 ft. 6 in. pitch and in 7 ft. 6 in. in 
diameter, designed for a speed of 195 miles an hour, which 
the machine is expected to make with full power. 



102 TEXTBOOK OF APPLIED AEROXAUTIC EXGIXEERIXG 







LAWSON 

M.T2. 

T R ACTOR 



SINGLE MOTOKKI) AKHOI'I.AN I - 



HIM 




The Law-son M. T. .' tractor biplane 

The Lawson M. T. 2 Tractor Biplane 



Tin characteristics of tin- M. T. 2 nre Approximately as 

follow * : 



S|.:in. upper plain- 
Sp.lll. low IT plane 



;t'l ff. 

Mi ft. 

.-, ft. J in. 

5 ft. 1 in. 

8 In. 



tt 

. upper plane (iiicliiiliii)! ailrroiis) ........... >00 si|. ft. 

. IIIUIT plane ............................... 1.X) sq. ft. 

Lrnjrth. over nil ................................. 25 ft. 

Hcittlit, OMT all ................................. 8 ft. 

-lit. rmpty ................................. 1,200 His. 

\\.-i_-M. L.Mlecl 
Speeil ranj:e 
Clinili. in In minutes 
Clidinjr anjrlr. full load 
Motor. II ,11 Scott 



1,900 His. 
4."-90 tn.p.h. 
6.0(X)ft. 
1 in 9 
100 h.p. 



Planes 



Both wings are in two sections, tin- top attaching by 
hiiii-i - to hinge ]>lii);s secured in the cabanc and the lower 
to plnn-, secured to fittings and cross tit- tubes in the 
fuselage. 

Tin- spars are of 1 section, having a high factor of 
>y (which incidentally is carried throughout the ma- 
rhinc on the more important parts). They are left solid 
at both internal and external strut attaching points and 
also wherever any bolts attach such as for the wing and 
aileron hinges. The ribs themselves are built of wood 
webs, reinforced with strips between lightening holes, and 
cap strips. Mahogany veneer forms the nose of the upper 
surface of both wings while false ribs are placed between 
the standard ribs from the entering edge to the front spars. 

Between spars the ribs are braced by stringers while 
bays are separated by square section struts channeled out. 

Double wiring takes all drift strains while single is used 
for truing up. These wires are given two heavy coats of 
red lend while all woodwork is given a coat of filler and a 
coat of varnish. 

Tin- ir nlniL' edge is ash, excepting at the inner ends of 

the wings and outer ends of the ailerons where flattened 

1 tubing is used. The outer edges are of steamboat 

white ash and slightly curved in plan view to take the 



tensionnl pull of the cloth caused through the contraction 
of the wing dope upon its application. 

Both wings are connected by two pairs of interplnnc 
struts on each side of the fuselage. These taper into cup 
sockets which arc fastened to the wing strut plates by a 
neat bolt and nut. The plates theniseKes are of the four 
bolt type whereupon the bolts clamp the spars and are 
prevented from sliding by blocks attached to the latter. 

The lift cables arc all doubled and are all of 1/s cable 
with the exception of the main lift and main landing wires, 
these being .1 

The ailerons work in conjunction with each other, being 
interconnected by cable guided through neat fairleads on 
top of the upper wing. Each is equipped with two sets 
of brace arms provided with shackles to take both brace 
and control cables. The control cables run through pul- 
leys down to the fuselage where they connect to a chain 
and arc safetied to each other as well. 

Fuselage 

The longerons and vertical struts arc of straight grain 
ash in front and spruce in the rear. The longerons are 
left solid their complete length, while all struts, both ver 
tical and horizontal, have been channeled but left solid at 
all points of connection. Steel tubes fitted into sockets 
are used for horizontal struts back to the rear pit and also 
to carry the load from the tail .skid shock absorbers. 

Owing to the constant section of both longerons and 
struts in the rear part of the fuselage the fittings are all 
standard and can be used at any of the stations in this 
section. The stern post is of tubing witli interchangeable 
fittings at upper and lower ends to take the longerons. 
Each pit is reinforced with ash rims as well as the tension 
wires to prevent any twisting effect caused by rapid 
manoeuvcring either on the ground or in the air, and it 
likewise acts as a protection in case of a " telescoping " 
landing. The whole fuselage is braced throughout by 
double cables in the front sections and wire in the rear. 

The engine bed rails rest on top of an ash cross-member 
and are secured to this by U-Bolts. The whole unit is 
braced by tubes fitted with plug ends. 



104 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Gallaudet E-L 2 Monoplane 

Striking originality in design is shown in the twin- 
pusher monoplane exhibition by the Gallaudet Aircraft 
Corporation. Mr. Gallaudet's 1919 Sport Model has a 
high factor of safety and is easily maintained. 

Two stock " Indian " motorcycle engines are located in 
the nose of the fuselage, connected to a common trans- 
verse shaft and resting on the top of the plane, and driv- 
ing twin pusher propellers on longitudinal shafts driven 
by bevel gears. 

Engines are " oversize " models, giving 20 h.p. each at 
2400 r.p.m. Weight, 89 Ibs. each. Propellers are 3 
bladed (2 bladed propeller on exhibition), 4 ft. 8 in. in 
diameter and 7 ft. in. in pitch. Propellers run at one- 
half engine speed, 1200 r.p.m. 

The plane has a span of 33 ft. in. and a chord of 4 
ft. 6 in. Wing tip ailerons are 7 ft. in. long and 1 ft. 



in. wide. Wing section, modified R.A.F. No. 15. Di- 
hedral, 178. 

The body is of monocoque construction, 3-ply spruce 
being used. Two seats are provided, side by side, with 
single stick control. 

Tail areas: Fin, 2 sq. ft; rudder, 4; stabilizer, 12; 
elevators, 8. 

Overall length of machine, 18 ft. 7 in. Special pat- 
ented true streamline wires brace the wings. For adjust- 
ment and dissembling a rod from one cabane to the other 
permits slackening of the cables and removal of planes 
without loss of adjustment. Turnbuckles are therefore 
unnecessary. 

Eight gallons of fuel are carried ; sufficient for 2 hours. 

With full load, a speed of 40-80 m.p.h. is attained. 
At present the machine weighs 750 Ibs., but new features 
will permit a reduction in weight to 600 Ibs. 




The small Gallaudet twin-motored monoplane. It is powered with two motorcycle engines. Its size can be estimated by com- 
parison with the seaplane above it. 

The Gallaudet E-L 2 " Chummy Flyabout " Monoplane 




1 Formation of the Gallaudet streamline cables. 2 How the upper part of the landing wheels are fitted into the 
monocoque body. 3 Right hand shaft drive from the engines to the pusher screw. 4 Bevel gear housing, connecting trans- 
verse driving shaft with the longitudinal propeller shaft. 5 Attachment of bracing cables at the cabane. 








IE PEBE FIGHTER 

400 HP 

LIBERTY 12' MGINE 



i ' V I 



106 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Side view of the American- 
built Le Pere Fig'hter, with 
a 400 h.p. Liberty Engine 



The Le Pere Fighter 



Captain G. Le Pere, an aeronautical engineer in the 
French Air Service, designed the " La Pere Fighter " with 
a Liberty engine. It was intended for use as a fighter or 
reconnaissance plane. 

General Demensions 

Span, upper plane 39 ft. Oy 4 in. 

Span, lower plane 39 ft. 0>/ 4 in. 

Chord, both planes 5 ft. 6 in. 

Gap between planes 5 ft. 0% in. 

Stagger 3 ft. 01% in. 

Length over all 25 ft. 4% in. 

Height over all 9 ft. 10% in. 

Weights 

Pounds 

Machine empty 2,468 

Pilot and Gunner 360 

Fuel and Oil 475 

Armament 352 



Total 3,655 

Performances in U. S. Army Tests 
Height Speed Time of Climb 

(feet) (m.p.h.) (min. and sec.) 

136 min. sec. 

6,000 132 5 min. 35 sec. 

10,000 127 10 min. 35 sec. 

15,000 118 19 min. 15 sec. 

20,000 102 41 min. sec. 

Ceiling, or h sight beyond which the machine will not 
climb 100 feet per minute, 20,800 feet. 

Main Planes 
Planes are flat in span and have no sweepback. Top 



plane is in three sections ; a center section over the body, 
and two outer panels. Lower plane in two sections at- 
tached at lower sides of fuselage in the usual manner. 

Upper and lower planes are similar in shape, and with 
ailerons 21% in- wide by 9l!/4 in. long attached to both. 
An interconnecting streamlined rod is used between each 
pair of ailerons, located behind the outer wing struts. 

Leading edge of upper plane is located 49 9/16 in. from 
front of propeller hub. Middle struts located 9-1"% in. 
from center of machine; outer struts, 98l/o in. from mid- 
dle struts; overhang, 41 in. Interplane strut design is 
unique inasmuch as it eliminates the usual incidence wires. 

Fuselage 

Veneer is used for exterior finish. Over all length of 
fuselage, 22 ft. % in. Maximum section at the gunner's 
cockpit, 32l/> in. wide, 45l/o in. deep. 

Center of gravity occurs at a point 6 ft. 3 in. from nose 
of fuselage. 

Axle of landing gear 22% in. forward of center of 
gravity. The landing gear wheels have a 6~> 9/16 in. 
track and are 28 in. in diameter. 

Tail Group 

Over all span of stabilizer, 98% in.; chord, 3 5 1/, in. 
It is fixed at a non-lifting angle, and attached to upper 
fuselage longerons. 

Tail flaps or elevators measure ISS 1 /^ in. from tip to tip. 
Their chord is 31% in., and in addition to this there are 
small balancing portions extending beyond the tail plane. 

Rudder is 30 in. wide and has a balancing portion above 
the fin, 25 in. wide. 



Three quarter rear view 
of the Le Pere Fighter 




SINCil.K MOTOKKI) AKHOIM. \M.S 



KIT 



It dcXrlops 

in.; wci-jlit. 
Two /enilh 



Engine Group 

\ I lIl.Tty " I'.' " II 10 h.p. engine IS lls.d. 

HH h.p. at \~:> r.ji.in. Horc. :. in.; stroke. 
without propeller and w it. r. s;,.s pound*. 
Duplex carburetors an us. d. 

The radiator is lm-.il.il in the ii|i|n r pi nn center section. 
anil its liN-atiiui has in 1-1 ssil.it. rl sonir slight iiinilitii-.itions 
in tin- rnjiini- to inrn-.isi tin \\ati-r i-irriilation. 

1'roin-llcr. ! ft. t in. in iliaindi-r. 1 runt |in)|M.*ller 
pl.-itr proju-ts ll :; , in. forw.-inl of fus, l.i^, ,,,, . 

I'mpt Ili-r .-t\is I.'. 7 hi in. In-low lop of npprr lonnrroiis. 
In Hyiiij; position tin- 'irop. lli r hull is .'. ft. ,' ; s in. alnnr 
tin- unniixi linr; \ilnn it n-st on tin- Around tin- propi-llrr 
hull is li ft. | :: N in. aliow ground. 




Left- h*Ml*. Tin- Irti-ion of Hi.- ri-nr brace wires lit 

oirri<-<l from mn- si.l<- of UK- l.in.linjr ger to the other liy a flat 

strel str.i]i, f.illnu injj nfti-r (In- ;i\l.- 
Kijrlit \ili-roii. iiitrr-riiiiiiiTtinjr strut imil <i|>rn>ti>ifr lr\rr, 

sliowinjr the means for adjiistmrnt in UK- u||M-r end of forked 

trrininal. 



Ordnance Engineering Scout 80 LeRhone 

This m.n-hine was tested at Wilbur Wright l-'ield by the 



I'. S. A mix 
Climb (ft.) 



Summary of Results 

Time Kate r.p.m. Speed r.ji.m. 

o 98 l. l-o 

<> min. 535 1.1 Hi 9i l.i;> 

10.000 ]T min. :U) sec. 31 . 1,100 84 1,175 

15,000 55 min. 1,100 70 1,100 



Service ceilinfr 13^00 ft. 

U .-iirht. empty s:i", |b-. 

Total weijrht of load i ll)t. 



Total weifrfit 1,117 Ibs. 





Ordnance Scout with M Ix-lthone 



Ordniince Scout with -n |.,-l(h..n.- 




Ordnance Scout with 80 I-elMnm. 




Ordnance Scout with 





THE Of .C " B 

160 HP GNOME 

SINGLE 5EATER 



Scale of feei 



Mclaughlin 



108 



SI\(;i.K MOTOHKl) AKKOIM.ANKS 



I line quarter front \iew- of the ( ). I ( 

Mnjle Srili-r Seoul Itiplalie 




The O. E. C. Types B and C Single Seater 



Tin type " ( " i- .in .iil.-iiit.-itiun of the Model "B" 
filthier. .-UK) with tlir e\re|>tinii that the staggers differ iti 
tin- two type- ind tin- t.-nik-. .-mil weight distributions are 

<li(i'rri-iit. tin m in-r.-il dimensions of the two types rem.-iin 
tin- s.-uii. . 

Gene'al Dimensions 

Spun. II|I|MT pl:uie ........................ -'fi ft. in. 

>p in. lower pl.-ine ........................ i3 ft. In. 

Chord, II|>|MT plum- ...................... 4 ft. O in. 

Chord. IIIM-IT filiuir ....................... ;{ ft. ft in. 

Cup. In-twi-fii pliitK-N ...................... 3ft. Sin. 

(K.-r.ill IniL'tli ........................... 19ft. in. 

Ovrnill hcijilit (pn.|x-ll.-r hiirizimtal) ...... 7 ft. 7 in. 

-IT ................................. 7 in. 

Areas 



pl.inr 
l.nwrr pliinr .................................. 77.H 

Ailrriiiis, np|T pliinr ......................... 175 

Total wing area (with Hili-nins) ............... 180. 



Kin 
Huildrr 



3.08 
5.4 



Weights 



Mixlrl It .M.Hl, I C 

1 1 weight, full liuifl .............. 1^90. 1.090. 

Wright ]M-r M|. ft. <if Area ......... 7.15 6.05 

Wright, pounds per h.p .............. 8.07 



Weights, useful Load Model C 



165 

ll.i-.i- ........................................ 7T 

Tail Group ...................................... JS 

l-'nginr ......................................... *90 

1'roprller ....................................... i3 

Tanks ......................................... 30 

Winp .......................................... 150 



Total 



Gaxolinr ........................................ 1*6 

Oil ............................................. 90 

1'ilnt ........................................... 180 

Fire Kxtinguisher, etc ........................... 16 



Total 



Weight Distribution 

( totals) 
Model It MiMteiC 

Strurturnl Weight ...................... :. 34.4 

1'ower I'lant ........................... i*3 34.79 

Furl and Oil ........................... 15.5 H.65 

Military or f.scful I.OHC! ................ i33 18.16 

Performances 
(Climh) 

Time 

Altitude (minutn) 

(f f fl) Model B MixlelC 



5,000 ................................. 3J 8 

10,000 ................................. 6.6 17 

15,000 ................................. 16. 40 

20,000 ................................. 96 A 

Oiling ............................... M 




Hear view of the O. F.. C. Type B 
Gnome Kngine Scout 



110 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The O. E. C. 80 horse-power Le Rhone training scout 



13(5 



(Speed) 
Altitude 
(feet) 



5,000 

10,000 

15,000 

20,000 

Ceiling 

Stalling Speed 51 

(Duration) 

Maximum ninge, at 10,000 feet 
Model B 

At full power 

At minimum power 



(Miles per Hour) 
Model B Model C 



104 
101 
96 
90 
83 
72 
33 



Model C 
2% hours 
3 hours 



Main Planes 

Aspect ratio of upper wings, 6. 5; lower wing, 6.14. 

Safety factor of wing truss at high speed, 6; at low 
speed, 7. Wings have no sweepback nor dihedral. Deca- 
lage, 1 degree. Angle of upper wing to propeller axis, 
1.5; lower wing, 0.5. 

Gap to chord ratio, 0.947. 

Wing section, R. A. F. Number 15. 

Clear vision is obtained forward through an angle of 
45 degrees between wings. The only blind spots are 
through an angle of 8 degrees for the top wing and 33 
degrees for bottom wing. 

Ailerons are 6 ft. 9 in. long and 1 ft. 7 in. deep. Cen- 
ter of pressure, 9 ft. 6% in. to longitudinal axis. 

Tail Group 

Stabilizer span, 7 ft. 6 in.; depth, 1 ft. 10 in. Center 
of pressure to center of gravity of machine, 11 ft. 10 in. 

Elevators are 8 ft. 2 in. in span; depth, 2 ft. in. Cen- 
ter of pressure to center of gravity of machine, 13 ft. 4 in. 

Rudder, 3 ft. 4 in. high and 2 ft. in. deep. Center of 
pressure to center of gravity of machine, 13 ft. 4 in. 

Fin, 1 ft. 8 in. high, 2 ft. 10 in. deep. Center of pres- 
sure to center of gravity of machine, 11 ft. 9 in. 

Landing Chassis 

Wheels have a track of 5 ft. in. Angle of center of 
gravity ground point and vertical 13l/> degrees. 



Chassis designed to stand up when fully loaded ma- 
chine is dropped from a height of 10 inches. 

Fuselage 

Length of fuselage, 15 ft. 11 in. Maximum section, 
3 ft. 5 in. by 3 ft. 5 in. 

Fuselage designed to stand a load of 30 pounds per 
sq. ft. on horizontal tail surface and dynamic loading of 5. 
Engine section has a safety factor of 10. 

The instruments on the dashboard are as follows: 
Dixie Magneto switch; Phinney-VValker rim wind clock; 
longitudinal inclinometer; horizontal inclinometer; Alti- 
meter (20,000 ft.); Tachometer, Signal Corps, type B; 
and a Sperry Air Speed Indicator. The clock, Altimeter, 
Tachometer, and Air Speed Indicator have Radiolite dials. 

A Pyrene fire extinguisher is conveniently mounted at 
the left of the seat, connected so as to be pumped directly 
into carburetor, or it may be used separately. 

Power Plant 

(LeRhone) 

The 80 h.p. Le Rhone engine develops its rated h.p. at 
1200 r.p.m. Fuel tanks are mounted between the engine 
and the pilot, over the center of gravity. 

Capacity of gasoline tank, 18 gallons, Oil, 4 gallons. 
Weight of gasoline, 110 Ibs., sufficient for 2*4 hours. 
Weight of oil, 28 Ibs., sufficient for 2% hours. Gasoline 
consumption, 0.60 pounds per b.h.p. hour. Oil, 0.13 
pounds. 

Propeller, 8 ft. 4 1 /. in. diameter and 7 ft. 6 1 /-; in. in 
pitch. 

Height of propeller axis above ground with machine 
in flying position, 4 ft. 11 in. ; with machine at rest, 5 ft. 
6 in. 

Power Plant 

(Gnome) 

The Gnome engine is of French manufacture. At 1200 
r.p.m. it is rated at 160 h.p. 

Gasoline consumption, .85 pounds per h.p. per hour; 
Oil, 16 pounds per h.p. per hour; Gasoline capacity, 35 
gallons; weight 210 pounds. Oil capacity, 4 gallons; 
weight, 28 pounds. 





THE MARTIN 

45 HP ABC ENGINE 
KDI SCOUT 



Scmim tf F..I 



Mclaughlin 



111 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Martin 
K-III Single 
Seater with a 
two cylinder 
Gnat A. B. C. 
engine devel- 
oping 45 h.p. 



The Martin K-III Single Seater 



Some of the distinctive features of the Martin K-III, 
15 h.p., single-seater, are retractable landing chassis, the 
K-bar cellule truss, wing end ailerons, and shock-absorb- 
ing rudder, which have been patented by Captain James V. 
Martin, the American aeronautic engineer. These fea- 
tures are interesting solutions of difficult aerodynamical 
and constructional problems and show the tendency of 
modern design toward the attainment of efficiency with 
low power rather than the employment of great power to 
overcome the disadvantage of uncertain design. 

The K-III was designed as an altitude fighter, and is 
equipped with oxygen tanks behind the pilot's seat and 
provision for electrically heating the pilot's clothing. The 
seat is so located that excellent vision is obtained; vision 
vertical circle from dip of , r > dead ahead through an arc of 
180; horizontal circle 360, transverse circle from dip of 
27!/2 through an arc of 235. 

The machine can light upon and start from a country 
road and can travel 22 miles on one gallon of gasoline, 
making it an economical means of carrying mail and light 
express in rural free delivery, etc. 

Dimensions 

Span, upper plane (without ailerons) 15 ft. in. 

Spun, lower plane 17 ft. 11% in. 

Chord, both planes 3 ft. 6 in. 

Gap between planes 4 ft. fi in. 

Length overall 13 ft. 3'/ 2 in. 

Height overall 7 ft. 4% in. 

Areas (Sq. Ft.) 

Upper plane (without ailerons) 53.50 

Lower plane 47.80 

Ailerons 5.00 

Stabilizer 9.50 

Elevators 6.66 

K udder 4.88 

Weights (Lbs.) 

Engine 85.50 

Wings 60.75 

Ailerons and supports 9.50 

Chassis and retracting mechanism 16.38 

Wheels 17.50 

Struts, wires and K bars 8.25 



Oil and gasoline tanks ................................. 9- 7;> 

Rudder and tail skid ................................... 7 - 75 

Damper and elevator .................................. 14.50 

Fuselage, complete .............................. 

Propeller and hub ..................................... 13.63 

Total weight .................................... :550 - 

Performance (Estimated) 
Altitude (Ft.)' Time.(Min.) Speed (m.p.h.) 





5,000 
10,000 
15,000- 
20,000 
25,000 





3 

6 

11 

18 

28 



speed 145 



135 
113 

HI 

108 
07 
m.p.h. at 



10,000 



(With 60 h.p., 100-lb. engine 
feet.) 

Endurance at 10,000 feet: 

At full power ..................... 223 miles 

At minimum power ............... 216 miles 

Main Planes 

The planes have neither stagger nor dihedral. 

The aerofoil of main planes is known as the " Ofenstein 
1." At 10 m.p.h. the Ofenstein wing section has a lift- 
drift ratio of 22 to 1. 

Upper plane is in a single continuous span. Wing 
ends are at right angles to the leading edge, and are 
finished off with a semi-circular termination which varies 
in radius as the wing varies in thickness. The half-round 
wing ends are characteristic of all the aerofoils of the 
Martin K-III. 

Principal wing spars for main planes are centered 14l/> 
in. back of leading edge, where the trusses carrying the lift 
are direct instead of bridged between the ribs. 

The front of main wing beam is coincident with the 
most forward travel of the center of pressure. 

The lower plane is in two sections, and attachment 
made to the fuselage. Wing ends are raked at an angle of 
1 5 degrees. 

Interplane bracing is of the " K-bar " cellule truss type. 
The head-resistance is reduced 4 per cent through the 
elimination of struts and wires. 



SINCil.K MOTORED .\ KHOIM.ANKS 



113 




1 unit \ i< ui tin- Martin Kill Scout, 



l>y C.i|it.iin .1 inn s \'. Martin, -mil comprising sonic of DM- special Martin feature-. 
The holding jrrnr is shown in it-, retracted position 



The percentage nf intfr i-i llule interference with the 
K-bar truss is \S -is i-mii]i:iri >1 with -'.'' '< in tin- standard 
truss; a total reduction of Hi' I. Of this reduction. 16% 
is due to tin- cliniiii.-itiiin of struts and win-s while- -i\''/c, is 
due to the increased gap obtained without subsequent 
weakening of truss or increase of structural resistance. 

K ^Iruts centered 1 t ft. from one another. The vertical 
member is ^ ft. .'('^ in. long; greatest section. I 1 t ill. by 
I 1 , in. The angular members of K-struts are attached to 
rear wing beams located 18 in. back of main beams. 
These members are of steel tube faired with sheet aero- 
metal. 

The vertical member of the strut is not subject to any 
bending moment at the juncture of the inclined members, 
for the upper member is in tension and the lower in com- 
pression, thereby neutralizing the forces at that point. 
The mid-strut fitting is designed with a view to equalizing 
the moments and relieving the vertical member of all 
c\c< pt the usual direct compression. 

l-'lying and landing wires are .3 16 in. diameter. Cen- 
ti r se.-tion .TOSS bracing is with ' s in. diameter wire. 

Tin- wing-end ailerons are an unusual departure from 
customarv aileron disposition. They have n righting influ- 
ence per square foot of area of t to 1 with the added 
advantage that they do not impair the efficiency of the 
aerofoil to which they are attached. 

The ailerons have a symmetrical double convex surface 
and are so balanced that their operation requires very little 
effort 

Ailerons are operated by means of a sliding rod running 
through the upper plane. Two cables running up the 
center panel struts cause the rod to slide from side to side. 
At the wing ends, the bar fits into a tubular collar attached 
to the ailerons. The collar is provided with a spiral slot 
or key way through which a pin from the rod projects. 
The sliding movement of the rod causes a rotary move- 
ment of the aileron collar. This method does away with 
all exposed actuating meml < rs. 



Fuselage 

Overall length of fuselage from engine plate to rear 
termination. 1(1 ft. 10 7 1(5 in. Maximum depth. X ft. 
(H, in. (not including streamline head rest); maximum 
width. -.' ft. -!'* in. 

The center of gravity is located 2 ft. 7 ' i- in. back of the 
engine plate. 

Veneer of ply-wood is used for the internal construction 
of the fuselage. 

In flying position, the top of the rounded turtle deck is 
practically horizontal. The upper longeron-, as well as 
the lower have an upward sweep towards the rear. The 
fuselage terminates in a vertical knife edge 18 in. high. 

Internal bracing of the fuselage is with solid wires 
looped over clips at the ends of cross-bracing members. 
Wires are run in series of four each, grouped in ribbon 
form. Each wire has a tensile strength of 2."it> Ibs. each; 
at the cross-braces, they run over a :< Hi in. radius. Only 
eight groups of wires and eight turnbuckles are required 
in the internal bracing system. 

The cowling and propeller spinner are of " aeromet.il. 
having the tensile strength of sheet steel at one-third of 
the weight of steel. 

Where engine cylinders project from the body, half- 
conical formers carry out a streamline. 

The fuselage is designed to stand a load of I OS Ibs. per 
sq. ft. of horizontal tail surface. Factor of safety, six. 

Instruments carried are: Altimeter, tachometer, gaso- 
line gage and oil gage. 

Tail Group 

The horizontal stabilizer has a span of 7 ft. 6 in. and 
width of 2 ft. (> in. Ends are raked at a 15 angle. 

The stabilizer is located in line with the center of 
thrust. It is fixed at a non-lifting angle and supported 
from below by a pair of steel tube braces. 

Elevators are 12 in. wide and have an overall span of 



114 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 





Engine mounting, Martin K-III 



Three-quarter re;ir view of the Martin 
K-III fuselage 



7 ft. 10 in. For rudder clearance, the inner ends of 
elevators are raked 30. 

Rubber covering between stabilizer and elevators closes 
the gap between the surfaces, giving a smooth, unbroken 
outline. 

There is no fin. 

The rudder is provided with balanced areas above and 
below the fuselage. 

The tail skid is contained within the rudder. It is pro- 
vided with rubber elastic shock-absorbing cord similar to 
the customary practice. It is especially effective when 
taxying on the ground. The combining of the rudder 
and tail skid does. away with considerable weight and air 
resistance while adding to the effectiveness and simplicity 
of the construction. 

The rudder is 1 ft. 10 in. wide; maximum height, 3 ft. 
5 in.; balanced portions project 8 in. forward of the prin- 
cipal rudder area. 

Flexible 3/32 in. cable is used for operating the rudder, 
by means of the usual foot bar. 

The elevators are actuated by means of a single % in., 
20-gauge steel tube from the control stick to a lever pro- 
jecting downward from the center of member forming the 
elevator leading edge. The fuselage terminates beyond 
the elevator leading edge, providing space for the enclos- 
ure 'of the operating lever. 



Landing Gear 

Ackerman spring wheels are used for the landing gear; 
these have 2 in. tires, and are 20 in. in diameter. The 
two wheels weigh 17 1 /' ^ )s - Wheel track, 2 ft. 5 in. 
When the chassis is extended, the underside of the fuselage 
at the forward end is raised 2 ft. 3 in. above the ground. 
When drawn up during flight, only the wheels are exposed. 

The front of axle and the two forward struts have flat 
front faces, so that when in flying position, these members 
fit flush into the fuselage bottom. 

A hand-operated worm gear, operated during flight, 
causes the chassis to be retracted with practically no 
effort on the part of the pilot. 

The landing gear has a factor of safety of 20. 

Engine Group 

The power plant consists of an air-cooled two-cylinder 
opposed " Gnat " A. B. C. engine, developing 45 h.p. at 
1950 r.p.m. 

Fuel consumption, .56 Ibs. per h.p. per hour ; weight, 
50.4 Ibs. Oil consumption, .017 Ibs. per h.p. per hour; 
weight, 1.55 Ibs. 

The fuel tank is located in the upper main plane above 
the fuselage. It has a capacity of 9.03 gallons, sufficient 
for a flight of two hours. 



SIX(iI.K MOTOKKl) AKKOIM.. \.\KS 



II.-) 



.ni Itipl.ini-, wilh -peri i! - 
cilinilcr I'.i.k.ird a\i.ili<m 




The Packard Aeroplane 



Tin- I'.-ickard two plan- tractor was ili-sim,,.,! around and 
in nli- i complete unit with tin- Model 1-A-TU Packard 
.\\iation r'.iipnc This in.-ii-liiiii- will make about loo 
m.p.li. with full lo.-id. on .-u-coniit of its li^ht weight and 
i li -.-in-i-iit design, .-mil \-i-t its landing S|H-K| is as low as the 
:I\IT:II;I- training aeroplane. 

I 1-1 cms* rniuitry trips ;in in nli- possible in (lijs .ship, 
with tin ability to land in relatively small fit-Ids. Tin- 
uriii ral spri-iticatinns are as follows: 

Power Plant 

r.-n-k.-ird s (vliiulcr KiO h.p. at l.)4."i r.p.m. \V ( -ij;lit. 
riiinplrtr with huh, startrr. battery and engine water, :>H.~, 
li>s. I in-1 consumption. ..',0 to .,U ll>s. per h.p. hour at 
sea level. 



Weights, Areas, etc. 



AreH, main plam-s 387 q. ft. 

Wright, innehinr <-in|ity . I^.Hl Ills. 

Normal flying wi-ijjlit ' .'.Hi; Ills. 

\\'ri)rlit. Ihs. |-r h.p l:..i His. 

Winfr lomliiijr, p<-r sq. ft .i.i> M". 

IVniiU~il.il- i-\tra luggage HXI Ihs. 



Altitmli- 



Performance (Estimated) 

Tim, of Climb 
(ininulc- ) 



Spi-i-il 
(m.p.h.) 



101 

100.5 
9 

15,000 (>o> 

Absolute ceiling, 19,500 feet. 



34.5 



I- ui-l rmifre 
(hrs.) 

:< 
U 

4 



SO.MK DI-.TAII.S OK TIIK I'\(K\HI) T\V(> SKVIT.lt Tit ACTOR 




I Tlx- shiM-k alisorlx-r arninp-mrnt. Thf axle is sqniirr, where it run* in the chassis slot. The elastic conl is iliviili-d into two 
(rron|is. one fore nml one nft of the nxle. i? The roomy suit ras ( - Iwker coinpnrtment Ix-himl the pilot's seat. A i, 

with ilov.-taiU-o 1 nlgrs tits IIMT tin- op<-nin(f. '.I Donlih- stilling cover plates an- ns.-il to |>rrmit rsy access to the unih-r 
>f tlx- engine in the vicinity of the air intake, projecting through the fnsrlnjn- Uittoin. 4 Wing construction. Webs are 
of thin mali,ii:.iii\ vi-ni-er. Cap strips anil triangular section |i-ailing edge of spruce. Short false rihs run from leading edge to 
main front heam. 5 Tail skid and anchor plate for stabilizer braces 





THE '5TANDA&D' M 

GNOME OR LERHONE ENGINE 

SECONDLY TWINING PLANE 



of /eel 



23*5 



116 



SIXC1.K MOTOKK1) .\KKO1M..\\KS 



117 




Hi. Standard Model K-l Sing 



"II ll |>. I I- Kllollr rll^ilir. 



The Standard E-l Single Seater 



Height 

(l-Vet) 
8,500 

10.000 



Summary of Performances (Continued) 
(With 1..- Hhone Kngine) 



Time of 
(limb 

Hi min. 30 s.v. 
-'-> min. 30 sec. 



II at.- of Climb 
Kt. |MT mill. 

900 



Speed 

(m.p.h.) 

90 

85 

(Viling, 14,500 feet. 
Stalling speed, 48 m.p.h. 
(Hiding angle, 1:7. 
Maximum range: At 5,000 ft., iOO miles; 10,000 ft., 160 mites. 



Tin " K I " Single Si.-itir was designed ; i s : , si-condary 
training machine. It is provided with either an 80 h.p. 
I ( Itlione or a 101 h.p. Gnome engine, but in either case 
the dimensions of the machine remain Ihe same. 

Tin- It. A. I'. No. I .'P wing curve is used. Dihedral. X r /i : 
aspect ratio of both planes. 7; stagger, 13.02 in. There is 
no sweepliack nor decalagc. Wings are set at an angle 
of 2 to the propeller axis. 

Maximum diameter of fuselage, K''-j in.; fineness 

General Dimensions 
Power Plant Feet 

(Lf Rhone) s l'" n - "PP" P' am> ** 

Span, lower plane 94 

Tin- I..- Khonc is a nine-cylinder, air-cooled rotary en- Chord, both planes 3.5 

gine developing 80 h.p. at 120O r.p.m. and 8 I h.p. at 1290. Gap between planes 4 

More and stroke. M Mi in. by .1 ' .. in. length over all ...18.85 

I'll, I tank located near center o*f gravity, has a capacity 

of 20 gallons. Fuel is consumed at the rate of .725 Ibs. . 

P-T h.p. per hour. Square feet 

Oil tank, located below fuel lank, has a capacity of 3 t'pper plane 81 

gallons. Oil is consumed at the rate of .03 Ibs. per h.p. Ix>wer plane 7J.: 

per hour Ailerons (J upper and J lower) 93.2 

Total wing area with ailerons 1533 

(Gnome) Stabiliser 19 

The nine-cylinder rotary Gnome, manufactured bv the * levator 19.7 

" * I** in -J fl 

General Vehicle Company, is known as tv|>e B-2. At .. 
I -i'ii r.p.m. it delivers KM h.p. Bore and stroke, 110 mm. 

by l.'.d mm. Summation of Weights 

Fuel tank has a capacity of 29.5 gallons; rate of con- (With !.< Ithonc Kngine) 

sumption. .81) Ibs. (>cr h.p. per hour. Wright in Percentageof 

Oil tank capacity, 5 gallons; rate of consumption. .20 pounds gross weight 

,. Power plant 434 36.4 

Ibs. per h.p. per hour. K,,, I ami oil 140 11.8 

Pilot and miscellaneous equipment. ... 179 15.1 

Summary of Performances Armament 98 9.4 

(With I-e Hhone Kngine) llody structure 141 11.9 

Height Speed Time of Rate of Climb Tail surfaces with bracing 36 3.1 

(Keet) (m.p.h.) Climb Kt. per min. Wing structure 156 13.1 

Ground 100-103 min. sec. 705 Chassis 74 6.9 

5,000 8 min. see. 705 

-..-."o 95 Total 1.188 100.0 



118 TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The VE-7 Training Biplane 



The VE-7 machine is designed around the 1 50 h.p. His- 
pano-Suiza 8-cylinder aeronautical motor, driving a direct 
connected two-bladed tractor air-screw. The entire 
power-plant unit, with all accessories, is mounted in a 
detachable forward section of the fuselage. 

General Dimensions 

Span, upper plmie 34 ft. 4 in. 

Span, lower plane 31 ft. 4 in. 

Chord, both planes S in. 

Gap between planes 4 ft. 8 in. 

Stagger 1 1 in. 

Overall length 24 ft. 5 in. 

Overall height 8 ft. 8 in. 

Areas (square feet) 

Main planes 297. 

Stabilizer 19. 

Fin 2.30 

Ailerons 37.42 

Elevators 17.09 

Rudder 7.8 

Main Planes 

Four aileron type, with cut-away top center section. 
The incidence is differential. 

No sweepback. Dihedral, 1^/4. Wings are in five 
units, assembled together with submerged hinges. In- 
ternal lateral control mechanism. 

Spars are of selected spruce, I-beam section, re-enforced 
at panel points. Ribs are of unit assembly type, built up 
of spruce and ash battens, with poplar webs, while for 
miscellaneous parts ash, birch and cedar are employed. 

The internal bracing system utilizes double swaged 
wires and forked ends attached to stamped mild steel fit- 
tings anchored to the main spars through neutral axles. 

Main plane fittings are submerged and the strut sockets 
are designed flush to the wing surfaces. 

Wing frames are covered with approved linen, or cotton 
fabric, specification sewed to ribs and " pinked " taped. 
Surface treatment is five coats of acetate dope and two 
coats of special grey enamel. 

Inter-plane struts are of selected spruce, solid one piece 
design, tapered slightly. The strut section is of very low 
head-resistance. 

Cellule bracing is Roebling 10-strand cable, fitted with 
Standard turnbuckles for adjusting means. Flying wires 
are doubled, landing wires single. 



Fuselage 

Carefully cleaned-up design of extreme simplicity. Fit- 
tings incorporate special anti-drift details. The frame 
is a box girder of steel and wood construction, unit type 
except for detachable engine mounting, with trussing of 
double swaged wires. 

Cross-section, rectangular but crowned top and bottom, 
tapering to a vertical knife edge at the rear. Dimensions 
at maximum section, 40 1 ';. in. deep x 30 in. wide. 

Motor housings and cowling are of stamped sheet 
aluminum, after portion being fabric covered. 

Cowlings enamelled light blue, fabric doped and grey 
enamel finished. 

Large, lunged vision doors render motor parts, control 
mechanisms and tail-skid system readily inspected and 
accessible. 

Seating 

Two seats, in very comfortable tandem arrangement, in 
well protected and upholstered cock-pits. Front seat be- 
tween wings, well forward to obtain vision. Cut outs in 
upper center section and lower wings facilitate vision from 
rear seat. 

Exceptional vision provided. Cock-pits fitted with re- 
enforced windshields. 

Longitudinal weights very close-coupled. 

Empennage 

Composed of fixed, double cambered st;ibilizer, con- 
nected dual elevator flaps, fixed vertical fin and balanced 
rudder. All frames are of steel, welded and brazed to- 
gether, wood rib filled, over tubular steel and spruce spars. 

System internally braced with swaged wires and car- 
ried externally by crossed cables and turnbuckles, giving 
a most rigid tail construction to withstand high stresses in 
" stunting." 

Empennage locked in place to fuselage by a series of 
exclusive design features. 

Tail units covered with wing fabric and finished to 
match. Doubled control wires connect up all control sur- 
faces. 

Chassis 

Type " V " strut and dual wheel design. Entire chassis 
quick detachable by removing 1 hinge pins. 

Wheels are 26 x 4 in., shod with Goodrich Cord Tires. 
Re-enforced stub axles of nickel steel operate in metal 



SI.\(;LK .MOTOKKD AKKOIM. \\ i - 



guide, with floating type shock-nbsorlH-rs assembled onto 

Illl-t.-ll spools. 

Axlrs. spreader tubes and sliock-ahsorhi r group well 
streamlined with stamped metal housings. 

" V " members of rll.-l-.--i-, are nf si leeti d brut ash. 

shock absorbers of ( ioodnch in. diameter clastic cord, 
cottiin sheathed. Wheels fitted with detachable st 
line fnlirir on ITS .-mil special oiling device. 

y IIII-III|MT in tin- complete chassis unit is pin con- 

. with adequate s.-it.t\ lurks, givinu -f at demount 

ability, desired llcxihility ;ind case of production, 

Met il parts finished in lilur enamel, baked on, while 
wood memhiTs .-in jjheii thn. oi.-its nt water-proof var- 
nish. 

Tail-Skid 

I itiiii: type skid, semi inmersal and si-lf-nlipiin^ in 
actic n. Is fitted with riil>ln-r cord sliork-alisorlier.s and 
ilile mi tal shoe. Assemlily ^rt-at-ablc through 
doors in ,idi of fnsclngf. All |iarts (|uick-detaehnble. 

Radiator 

Sp. .i,l hoiie\ eomli t\pe. located iii nose of fuselage, 
hoiisrd ill polished aluminum shell. Is eipiipped with 
dash hoard controlled slnitti r s\stem to reflate ciM>ling. 
Total water capacity in circulating system is ;pl , gallons, 
distance water thermometer installed. 

Oil radiator protruding Ix-low the under cowl is pro- 
vided in the oiling system. Including the capacity of the 
oil tank, the circulating s\ stem hold.s a total of five gal- 
lons of Inliricating oil. sufficient for over four hours wide 

i n tl\ ing. 

Fuel Tanks 

Two in numlier, main under rear seat, other in cowl 
M i n^iiie and dash-hoard, front cock-pit. Total 
fuel capacity is ;i I gallons, sufficient for over 2*4 hours at 
wide open throttle around sea-level. 

Carburetor supplied liy mechanical pump incorporated 
in motor. Hand air pump on dash for starting. 

Fin 1 shut otl' cocks in both cock-pits. 



Mufflen 

sheet steel tubular exhaust pipes extending along 
.sides of fusel ii;, back to rear cock pit. one on , a, b >,d. 
1'ipis supported by forced SIM-| brackets. 

Control* 

Dual stick control of new d. SI U MI. comliined with stand- 
ard type adjustable fi>ot rudder bars. Control syst. 
semblcd as unit ami installed with k bolts only. Knginr 
throttle lever and altitude adjustment control pn.\ id. d in 
both cockpits. Starting magneto crank in rt-ar cock -pit 
only. All controls have thumb-screw tension locking de- 
rfaM. I. \.rs and parts nickel plated, polisl , ,| 

Starting 

Self-starting of engine obtaimd by special hand oper- 
ated .starter magneto. Rear dash cijuippcd with I.unken 
In iinir hand primer to motor to facilitate cold weather 
starting. 

Safety ignition switch visible to mechanic cranking also 
provided. 

Instruments and Equipment 

Altimeter, air sp< . -d indicator, \\althim clock, tacho- 
meter, gasoline and oil pressure gauges, primer. Boyce 
I.. 1). thermometer, fuel controls and Dixie switch, all 
arranged on unit dash-board. 

Equipment includes fire extinguishers, safety belts, small 
tools roll and miscellaneous small parts replacement kit. 

Engine 

Hispano-Suiza, 8 cyl., 130 h.p., water-cooled type, 
Model A. 

Propeller 

Liberty 2-bladcd, walnut, 8 ft. 4 in. diam. x 5 f t 5' - 
in. pitch. 

Factor of Safety 

A uniform factor of safety of U plus has been proved 
for the design by the latest French methods of sand load- 
ing. 







e Three-Motored White 
Monoplane 



Tin dimensions of the White 
lonoplnnes are: 

spread. 82 f eet ; length 
vcrall. 39 tot; height to top of 
weight empty. .S.7HO 
omul-. Total Inirscpowi r. 660. 
d by three Hispano-Sui/.a 
lues. Two I so H. P. engines are 
itnl .me on each wing on each side 
-dy. The third engine. .SOU 
1 I' . ;s installed in the nose of the 
^B as in single-motored aero- 
Tin- winas have a sweep- 
u-il tips and an angle of in 
of four degrees. 




120 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The " Standard " Type E-4 Mail Plane, which has a capacity for carrying 180 pounds of mail. 

engine the machine makes a speed of 100 m.p.h. 



With an Hispano-Suiza 150 h.p, 



The Standard Model E-4 Mail Aeroplane 



Mail is now carried between New York and Washington 
in the specially built " E-4 " mail machine brought out 
by the Standard Aero Corporation. 

General Dimensions 

Span, upper plane 31 ft. 4% in. 

(Span, upper plane with overhang) 39 ft. 8% in. 

Span, lower plane 31 ft. 4% in. 

Chord, both planes 6 ft. in. 

Gap between planes 5 ft. 6 in. 

Stagger 5y 4 in. 

Length overall 26 ft. 1 in. 

Height overall 10 ft. lOy^ in. 

For winter flying, overhang extensions are attached to 
the ends of upper wings, increasing the span from 31 ft. 
4% in. to 39 ft. 8% in. 

Areas 

Square 
Feet 

Upper plane 1T4.9 

( Upper plane with overhang) 230.3 

Ailerons (2 upper and 2 lower) 48. 

Ailerons (with overhang) 56. 

Lower plane 162.1 

(Total wing area, with overhang) 382.4 

Stabilizer 23.7 

Elevator 22.0 

Fin 4.6 

Rudder 10.1 

Weights, General 

Pounds 

Machine empty 1,566 

(Machine empty, with overhang) 1,616 

Fuel and oil .". 390 

Useful load 444 

Total weight, loaded 2,400 

(Total weight, loaded, with overhang) 2,450 

Weight per h.p 14.1 

Weieht per sq. ft 7.12 

(With overhang; weight per h.p.) 14.4 

(With overhang; weight per sq. ft.) 6.4 



Summation of Weights 

Weight 
(Ihs.) 

Power Plant 778.5 

Fuel and Oil 390. 

Pilot and miscellaneous equipment .... 364.3 

Mail 180.0 

Body Structure 288.1 

Tail surfaces with bracing 75.5 

Wing structure 324.0 

Chassis 100.0 



Percentage of 

Gross Weight 

32.4 

16.2 

11.0 

7.5 
12.0 

3.2 
13.5 

4.2 



Total 2,400.0 



100.0% 



WEIGHT SCHEDULE 
Power Plant 

Pounds 

Engine complete with carburetor and ignition system 455 

Radiator 74.5 

Water 75 

Fuel and Oil Tanks empty 50 

Propeller and Hubs 27.5 

Cowling 61.5 

Pipes, etc 35 

Total 778.5 

Fuel and Oil 

Fuel (60 gallons) 360 

Oil (4 gallons) 30 



Total 390 

Pilot and Equipment 

Pilot and clothing 170 

Dashboard Instrument ; 32.25 

Miscellaneous 62 



Total 264.3 



Mail 



Mail 



180 



Total 180 



SIXCJLK MOTOKK1) A KKO1M.AN KS 



Uody frame 






Body When overhang section is used, top of inclined struts 

irt i i uteri d I ft. s'_. in. from outer struts, leaving an 

o\erhang of -.'.'' -. in. 
vats ami Moor II. .1 

Kront ami rear control .':'.7:, I''"' " Spad " truss is used between the planes, having a 

steel tul>e coinpression member l-t. en front and rear 
Total -'--.! middle struts. here Hying and landing cables cross. 

Tail Surfaces with Bracing 

Fuselage 

ili/.rr .4.0 

'.lectors I ' The engine is carried on a pyramid type support. 

Mail is carried in a compartment situated at the center 

{udder 9.5 , . , . 

.... .?, of gravitv. |iist forward of the pilot s cockpit. 

I.I',, I it I II iu ^t w I ri , (it vi.tj 

\\hen the uiaeliine is at rest, the propeller axis is (5 ft. 

Total T.i.j in. above ground; in Hying position it is ."> ft. (I in. above 

Wine Structure ground. In Hying position, a line from wheel base to 

. . center of gravitv makes a 11" angle with a vertical line. 
I pper wmjr with lilting and ailerons 143.4 

Lower wimritli lilting ami ailerons 129.4 A "- r1 ' between lin. joining wheel base and skid to a 

Interplane Struts and cables .1. liori/ontal line. II d< - minutes. 

Tlie stabilizer is fixed at a neutral angle. 

Total 3-M.il 

Chassi8 Landing Gear 

Wheels eo-nplete; Axle; Shock Alisorber, and I'nrts '> 

{ Wli.-el Type l.andinir (Scar 93 The usual two-wheel landing gear is used, hut provision 

is made for the attachment of a third wheel, ax shown in 
the drawing, which adds 25 Ibs. to the weight. 

Performances Steel tube is used for chassis members, faired with 

Height Speed Timeof Climli Rate of Climb spruce streamline stiffening pieces. 

(ft.) (m.p.h.) (min.) (ft. per min.) 

100 700 

.WM) 10 Engine Group 

10.000 ... 24 

S, .,.<! 40 m.p.h. The engine is a Wright-Martin Model I Hispano- 

Vi'i-'l'- 1 to 8 Suiza, giving 150 h.p. at 1500 r.p.m. and 170 h.p. at 

Maximum Range 280 miles l7()OrDm 

Hours ruL'lit. full speed at 4,000 feet 3 hours , , . 

The model I is an 8 cylinder V type with a bore of 120 

Main Planes mm. (t.724 in.) and a stroke of ISO mm. (5.118 in.). 

Both planes are swept back at a 5 angle, and both have Zenith Carburetor and magneto ignition are used. 
a r; or 1% dihedral. There is no dccalage; the inci- F.ngine weight, with propeller. 155 Ibs. Propeller, 

or angle of the wing chord to the propeller axis is 9 ft. in. in diameter. 

oi.. Fuel consumption, 0.51 Ibs. per h.p. per hour; oil con- 
Wing section. R.A.F. 15. Aspect ratio of both wings, sumption, 0.03 Ibs. per h.p. per hour. Fuel tanks are lo- 
-hen overhang section is not used. cated at the center of gravity; their capacity is 60 gallons. 
I'ops of center section struts are spaced 32% in. from Oil tanks located underneath the engine; capacity, 4 gal- 
cent, r to center. Middle struts 5 ft. 8 in. from center Ions, 
ection struts; outer struts 6 ft. 3 in. from middle struts. The nose radiator is of the Livingston type. Water 
This leaves an overhang of 33 1 /;: in. capacity, 9 gallons. 




Three-quarter rear view of the Standard Model E-4 Mail Aeroplane 



Compartment for carrying mail on 
Hi, " Standard " Mall Aeroplane 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Thomas-Morse S-4C single sealer advanced training scout with an 80 h.p. Le Rhone engine 



Typt 



Thomas-Morse 
-S-4C Single-seater Scout 



General Dimensions 

Length 19 ft. 10 in. 

Spread 26 ft. 6 in. 

Height 8 ft. 1 in. 

Weight and Lift Data 

Total weight loaded '. 1330 His. 

Area lifting surface (including ailerons) 234 sq. ft. 

Loading per sq. ft. of lifting surface 5.7 Ibs. 

Required horse power 90 

Weight of machine loaded per h.p 14.8 

Power Plant 

Type of engine 80-h.p. Le Rhone (air cooled rotary) 

Engine revolutions per minute 1250 

Fuel capacity, 30 gallons, sufficient for 3%hours' flight at full 

power 
Oil capacity, 6 gallons, sufficient for 4</ 2 hours' flight at full 

power 

Propeller type 2 blade 

Propeller diameter 8 ft. 

Propeller revolutions per minute 1250 

Chassis 

Type " Vee " 

Wheels 2 (tread 5 ft.) 

Tires 26 in. x 3 in. 

Area Control Surfaces 

Ailerons 25 sq. ft. 

Elevators 16.8 sq. ft. 

Rudder 8.5 sq. ft. 

Horizontal stabilizer 16.8 sq. ft. 

Vertical stabilizer 3.5 sq. ft. 

Stick type control used. 

Performance 

High speed 9T miles per hour 

Low speed 45 miles per hour 

Climb in first ten minutes 7500 ft. 

Thomas-Morse 
Type S-4E Single-seater Scout 

General Dimensions 

Length 19 ft. 4 in. 

Spread 22 ft. 6 in. 

Height 7 ft. 



Weight and Lift Data 

Total weight loaded 1 150 Ibs 

Area lifting surface (including ailerons) 145 sq. ft 

Loading per sq. ft. of lifting surface S Ibs 

Required horse power '. 9( 

Weight of machine loaded per h.p 12.S 

Power Plant 

Type of engine 80-h.p. Le Rhone (air cooled rotary j 

Engine revolutions per minute 125( 

Fuel capacity, 20 gallons, sufficient for Sy 2 hours' flight at full 

power 
Oil capacity, 4 gallons, sufficient for 3 hours' flight at full power 

Propeller type 2 hlad< 

Propeller diameter 7 ft. 6 in 

Propeller revolutions per minute I25( 

Chassis 

Type " Vee ' 

Wheels 2 (tread 5 ft.) 

Tires 26 in. x 3 in 

Area Control Surfaces 

Ailerons 16.4 sq. ft 

Elevators 16.8 sq. ft 

Rudder 7.3 sq. ft 

Horizontal stabilizer 11.2 sq. ft 

Vertical stabilizer 3.8 sq. ft 

Stick type control used. 

Performance 

High speed 112 miles per houl 

Low speed 55 miles per houi 

Climb in first ten minutes . 8500 ft. 



Thomas-Morse 
Type S-6 Tandem Two-seater 

General Dimensions 

Length 20 ft. 8 in. 

Spread 29 ft. in. 

Height 8ft. 10 in, 

Weight and Lift Data 

Total weight (loaded) 13S.1 Ibs. 

Area lifting surface (including ailerons) 296 sq. ft. 

Loading per square foot of lifting surface 4.68 Ibs. 

Required horse power 

Weight of machine (loaded) per h.p 15.4 Ibs. 



SINCil.K MOTOKK1) .\KHO1M..\.\KS 



128 




Tile Thomas-Morse Type S I I Ills ;i uilll.' spi-enl ,if .' .' fert. It 

I.e Khonr. It has a speed : ,, to ||.' m 

Power Plant 

f ciiirine so-h.p. I..- Khonc (air coolrtl rotary) 

Kiigine rcMilutinns per miniiti- 

I M. I raparit}. Jn gallon-., snffirient for ly, hours' flight at full 

power 
Oil raparity. t gallons, sufficient for :t hours' flight at full |x>wer 

Propeller t} |H- _> |, lnde 

Pni|'llrr diameter 7 fj ]<> j n 

I'roprllrr reinliitions |x-r ininutr I 

Chassis 

- Vee " 

-1 (tread 5 ft.) 

T ' ri " M in.x3 in. 

Area Control Surfaces 
Ail, n.ns: (four) 31.5 gq. ft. 

'''> ''"- 16* sq. ft. 

Kuddrr 8.5 sq. ft. 

I lori/nntal stabilizer 14.5 M|. ft. 

Vertical stabili/.rr 3.5 sq. ft. 

Stick tvpr control used. 

Performance 

High speed 105 miles per hour 

I .,m s|ieed 40 miles per hour 

Climb in first ten minutes 8000 ft. T} |n- 



I.I.VI pounds and is powered with an H<| horsr-pourr 
iles per hour and 1 1 feet in ID minutes. 

Thomas-Morse 
Type S-7 Side-by-Side Two-seater 

General Dimensions 

"> .'I ft. i, in. 

Spread 't ' ft 

Height 9 ft 

Weight and Lift Data 

Total weight loaded 1480 Mis. 

Area lifting surface (Including ailerons) 3ti M\. ft. 

Loading per square foot of lifting surface 4. Ibs. 

Kequiml horse power ..90 

Wright of machine loaded |>er h.p 16J Ibs. 

Power Plant 

Ty|- of engine 80-h.p. I.e KhSne (air cooled rotary) 

Kngine revolutions |>er minute i .'.JD 

Fuel capacity, X) gallons, sufficient for 1' .. hours' flight at full 

power. 
Oil rapacity, gallons, sufficient for 3 hours' flight at full power. 

Propeller ty|>e .'-blade 

Proprllrr diameter 8 ft 

Pro|)eller revolutions p<-r minute 

Chassis 



Vee' 



view of the Thoma>-Mors< 





wing fitting at the left outer strut, 
Thomas-Morse Siile-liy-Side Tractor; 
an eye-bolt running through the turn- 
buckle plate attaches the strut fitting 
to the wing beam 



124 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Thomas-Morse S-7 80 h.p. Le Rhone engine, side-by-side two-seater, designed particularly for pleasure flying. 

Wheels 2 (tread 5 ft.) Vertical stabilizer li.G sq. f.t 

Tires 26 in. x 3 in. Stick type control used. 

Area Control Surfaces Performance 

Ailerons: (four) 40 sq. ft. High speed 90 miles per hour 

Elevators 16.8 sq. ft. Low speed 40 miles per hour 

Rudder 8.5 sq. ft. Climb in first ten minutes 6TOO ft. 

Horizontal stabilizer 14.5 sq. ft. 

The Thomas-Morse Type M-B-3, 300 H.P. Hispano Engine Fighter 




-Streamline cap at wire crossing, middle interplane strut. 2 T.eft lower front strut socket. 3 Empennage, showing the un- 
usual arrangement of the elevator lever which is run on the inside of the vertical fin. 4 Operating arm on top of upper 
aileron. At the right is shown a sketch of the unique junction for attaching streamline wires to flexible aileron control cable. 




Thomas-Morse type MB-U single-seater fighter, equipped with 300 h.p. Hispano- 
Suiza engine. Span, 26 ft.; length over- all, 20 ft.; height, 9 ft. 1 in. Total 
weight loaded, 2050 pounds. Fuel and oil capacity for three hours' flight at full 
power. High speed 163 2/3 m.p.h., climb to 10,000 feet in 4 minutes 52 
seconds. 



SIMil.K MOTOKKI) AEROPLAN] - 



< _ . .. *.v ~ " .A * "I- rv . Z..7T ^ 



^iwl,!,!,.!,!^ ,li 







(irm-ral urrHiigi-iin-iit, and MMIW dt tails, of the Frrnrh A.H. biplane 



h 




/-/< C/./f . 



T^.. , *~+-*~t, 

-C-^J / O^mnjjor C- 

Ji^VWJ- 





FRENCH A .R. T yP /. 



Plan and elevation of the fuselage of the French A. R. biplane 



126 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Four views of the French A.R. biplane 

The French A. R. Biplane 



This machine, designed by Commander Dorand, of the 
French Army, is designated as A. R. or A. L. D., according 
to whether it is fitted with a Renault or with a Lorraine- 
Dietrich engine. The machine is a two-strutter biplane 
of 13.30 m. span, and has its fuselage supported between 
the planes on ash struts. Sweep-back and dihedral angle 
are only present in the lower plane. The former amounts 
to 1 deg., while the dihedral angle is 2 deg. The top 
plane is staggered backwards 0.5 m. The gap is 1.825 
and 2 m., respectively; that is to say, in the centre it is 
0.945 of the chord. The angle of incidence of the upper 
plane is 2.5 deg., that of the lower plane 3 deg. 

The halves of the wings are screwed together in the 
centre of the machine. The wing spars appear to be of 
one section, covered on both sides with three-ply. Be- 
tween every two ribs, whose spacing is 300 to 340 mm., is 
a short false rib on the top surface only, running from 
the leading edge to the front spar. The wing fabric, 



which is of a cream color, is sewn to the ribs. In front 
of the trailing edge, which is formed by a wire, as in all 
French machines, eyelets are incorporated. 

The plane struts, which, with the exception of those 
secured to the body, are of hollow section, are of stream- 
line form. In order to prevent lateral bending the outer 
plane-struts are provided with a peculiar bracing. In 
addition the middle of the struts are braced to one another 
and to the bottom of the body struts. The strut fittings 
are of a very simple type, as shown in one of the illustra- 
tions. Strut sockets of sheet steel are secured to the 
spars bv U bolts, the two shanks of which pass through 
the spar and are secured by nuts on the other side. The 
flying wires and landing wires are anchored to the corners 
of these U bolts, while the incidence wires are secured to! 
lugs projecting from and forming part of the steel plate 
bottom of the strut sockets. This bottom is simply resting 
inside the socket and is not secured in any other way. 



SINCil.K MOTOKKI) A KHOl'LA.N KS 



r-'T 



The wing bracing consists of solid wires throughout, 
whifh arc corniced d to tin 1 fittings :iiul turnlmrklrs in the 
usual way by bending them OMT and sliding a ferrule of 
spiral wire OMT the free end. The Hying wires are in 
dii|ilie:ite and lie line In hind the other. The space be- 
tween them is tilled with a strip of wood. The external 
drift wire running to the nose of the Imdy is wrapped with 
thin cord to prevent it becoming entangled in the propeller 
in ease of breakage. Hctuccn the fuselage and the lower 
plane there is diagonal bracing in the plane of eaeh spar. 
As. howe\er. there is no corresponding bracing aho\e the 
fuselage, the upper ends of the top plane body struts are 
allow eil a eoiisideralile amount of play. 

\on hal meed ailerons. positively operated, are hinged 
direet to the rear spar of the top plane only. The aileron 
eontrol cables are in the form of simple cables running 
from the sprocket wheel on the control column, around 
pulleys in the lower plain-, along the lower side of the 
lower plane and under another pair of pulli \ s. From this 
point on tin \ are in the form of solid wires of 2 mm. 
diameter riinnini; to the aileron crank lexers, which are in 
the form of quadrants. The upper cranks of the ailerons 
are connected by cables and wires running across from 
side to side, along the upper surface of the top plane. 

At tin- stern of the fuselage is fixed a small tail plane to 
which is pivoted the balanced trapezoidal elevator. The 
rudder is also balanced. The rudder post is braced to the 
cletator. and this in turn to the body, by stream-line steel 
tube struts. The ends of these struts are flattened out 
and bolted to the various fittings. There is no vertical fin. 
The rudder is controlled by plain wires of 2.5 mm. diam- 
eter. Only where they pass over pulleys have cables been 
substituted for the wires. 

The undercarriage struts are secured to the spars of the 
lower plane at the points where occur the attachments for 
the struts running to the body. The short body struts are 
braced by stream-line tubes fore and aft to the body. The 
one-piece axle rests between two cross struts of steel tube. 
The travel of the axle is not restricted. The undercar- 
riage is braced diagonally in the plane of both pairs of 
struts. 

Tin- longerons and struts of the fuselage, which is fabric 
covered, are made of ash up to the observer's seat. From 
there they are made of spruce. The struts of the rear 
portion of the fuselage rest on the longerons without any 
attachment, and are held in place by the bracing only. 
To prevent them from sliding along the longerons the 
ends of the struts are notched to correspond with the shape 
of the wiring lugs, which surround the longerons. 

The 8-cylinder, Vee type Renault motor develops, ac- 
cording to a plate in the pilot's cockpit, 190 h.p. at 1550 



to 1 tii MI r.p.m. The radiator is placed between the body 
and the lower plane. Then is a shutter arrangement for 
varying the cooling. A water collector or (.ink is placed 
above. the port row of cylinders. The exhaust gases are 
carried outwards to cadi side through short collectors. 
\\'ith the older motors the exhaust from both row of 
cylinders was carried inwards to a common collector car- 
rying it up above the top plane, an arrangement which 
greatly hampered the \ n w of the pilot. In these machines 
the radiator was in the nose of the body. An auxiliary 
radiator was placed In-low the fuselage. 

The motor is bolted to two channel section steel bearers, 
which rest on strong sheet st, , I cr idles. Imm.diit. Iv be- 
hind the engine is placed transversely the oil tank, which 
has a capacity of 7 litres. Tin- main petrol tank, which 
has a capacity of I7< litres, is divided into three com- 
partments, and :> placed behind the pilot's seat. From 
here the petrol is pumped into a small gravity tank holding 
1-' litres and placed behind the engine. For this is em- 
ployed either a pump driven by the engine or a hand pump 
to tlw right of the pilot. If too much petrol is pumped 
through it is returned to the main tank via an overflow. 

The pilot sits in a line with the leading edge of the top 
plane. Here he has a very good view forward, but the 
view in a rearward and upward direction is very restricted. 

On the instrument board in front of the pilot are the 
following instruments: A cooling water thermometer, 
ignition control, compass, petrol cock and revolutions in- 
dicator. To the right, at the side of the scat, is the petrol 
hand pump elevator. On the left are the levers for 
advancing or retarding the ignition, the petrol and air 
levers, the radiator shutter control, and the oil cock. In 
the floor of the fuselage, in front of the rudder bar, there 
are small windows. 

In the observer's cockpit there are two folding seats, 
one in front and one at the rear. In front, behind the 
petrol tank, there are on each side racks for four bombs. 
Between these racks, through an opening in the floor, the 
photographic camera can be inserted. A shelf for plate 
holders is placed behind the port bomb racks. On the 
starboard inner wall of the observer's scat are aluminum 
plates for the switches and keys of the wireless. The 
other instruments of the wireless are placed aft of the 
seat. 

The pilot is armed with a fixed machine gun placed on 
the right-hand side above the body, and is operated from 
the left cam shaft. Firing is accomplished by Bowden 
control from the control wheel. The observer has two 
movable machine-guns, coupled together and mounted on 
a gun ring with elevating arrangements. 



128 



TEXTBOOK OF APPLIED AKKOXAUTTC ENGINEERING 




A French Breguet bombing machine in flight. On the rear can be seen twin Lewis guns mounted for use of the aerial photog- 
rapher or observer 

The Breguet Biplane 



This biplane, characterized by two sets of struts, is pro- 
duced almost exclusively of aluminum, and is intended for 
bombing purposes. The upper planes have a backwards 
stagger of 0.21 m. and a span of 1-1.4 m., and are mounted 
on a cabane frame, while the lower planes have a span of 
13.77 m. 

Both upper and lower planes have large cuttings at the 
fuselage and their arrow shape amounts to 175 deg. The 
angle of incidence of the upper planes is 4.5 deg. in the 
middle and 2.5 deg. at the ends, that of the lower ones 
decreasing from 3 deg. to 2 deg. 

The spars of both planes are drawn aluminum tubes 
of rectangular section 65.6 x 31.6 mm. The thickness of 
the walls of these tubes amounts in the inner section of 
the upper plane to 2.6 mm., elsewhere to 1.6 mm. The 
rear spar grows thinner towards the wing tips till the 
thickness of the edge, where auxiliary spars with ash bands 
of 6 mm. thickness and 3 mm. three plywood glued to both 
sides are provided. At the points of juncture and at the 
ends of the stampings the spars are strengthened by ash 
pieces, in some instances of I shape. A socket of 20 cm. 
length, made of welded sheet steel of a thickness of 1.5 
mm., is provided at the strut ends of the upper planes and 
at the strut bases. These sockets and the wooden linings 
are held in position by iron tube-rivets. 

The main spar of the upper plane is strengthened in the 
interior section of a pine support of a thickness of 10 mm. 
being fixed to one side of the spar by means of small 
brass screws. The spars of the upper planes are equipped 
with compression supports at the joints of the two sets of 
struts and the lower planes for the outer strut set, the 
support being an aluminum tube of the diameters 30 and 



27 mm. exterior and interior. Further there are two 
aluminum ribs of a width of 40 mm., one at the beginning 
of the ailerons and one by the bomb store in the lower 
plane. The interior wiring consists of single wire. 

The ribs are very strong. They have a depth of 2 mm. 
above, of 1.9 below. A web provided with weight dimin- 
ishing holes is glued between the longitudinals of three- 
ply wood, 3 mm. thick. On both sides of the spars as well 
as at five points between them the flange is strengthened 
by glued and nailed birch laths and wrapped bands. The 
ribs are arranged loosely on the spars. The ribs lie par- 
allel to the axis of longitude, forming in relation to the 
spars an angle corresponding with the arrow shape. They 
are connected with each other by means of the veneer 
planking, reaching on the upper side from the leading 
edge to the main spar, as well as by the leading and trail- 
ing edges. Further they are connected by two bands, 
lying behind each other and alternately wound from above 
and below the ribs. The distance between them amounts 
to 40 mm. Forward and in front of the rear spar more 
1 mm. thick auxiliary ribs of plywood are arranged. To 
reinforce the aerofoil, thin birch ribs reaching to the trail- 
ing edge are screwed to the rear of the ribs on the under- 
side. 

The yellow-white colored fabric is sewed to the ribs 
and secured with thin nailed strips where exposed to the 
air-screw draught. The provisions of hooks and eyes on 
the under side of the planes behind the leading edge and 
in front of the trailing edge is to permit the draining off 
of moisture. 

The part of the lower plane lying behind the rear spar 
is hinged along its total length and is pulled downwards by 



SIMil.K MOTOKK1) AKKOl'l.AM.s 



in' in-, of I -J nil. In r cords fi\.d on tin- under s.de ..I the 
ribs, tlu- tension of these r.-m IM adjusted In means >< 
scr.ws. .in :iiitoin;itic cli.in^i ot tin- :iiTiif<ii| corrcspondin:; 
with tin- load and speed thus results with ;in easier rontrol 
of tin aeroplane with .-mil without .1 lo ul nt bombs. The 
-' [lupines lur tin- dinars of tin- ailerons ;tnil tin flexible 
lower plane pieces cmliracc the spars anil in connected 
with them I >y means of liolts passim; riijlit through. Tin 
spars hail- no linings at thesr po.nls. 

The coiistrm (ion of tin stampings nf the spars is \<r\ 
simple. Several sheet steel pieces with corresponding 

in fixed to tin spars with two screws p 
tratiiij; them. 

The interplaiie struts are made of streamlined aluminum 
tiilies with aluminum sockets in lioth ends. The inner 
struts are further str< -ngtln neil liy tin- insertion of rivcteil 
( irons. The aluminum employed his a stn iii;th of H> 
kg. |>er s(|. Him. with a stretching of 18 per rent. The 
l ndinj: figure is I 2. 

The I-..! nun. thick load-carrying cables are double, the 
spaee lietwicn tin in being tille<l by a wooden lath. In the 
same manner the landing wires as well as those crossing 
from the up|M-r planes forward and backwards of the 
fust-lap- are arranuid. In inj; wires of a thickness of .''- 
mm. that are connected with the .stampings and the turn- 
buckles in a primiti\e way |i\ means ot CMS and spiral 
wire pushed over. To give a l>t-ttcr support to the lower 
planes, beinir much stressed by the |MIIII|I .store, the load- 
carrying cables are in the inner section led to the stamp- 
ing on tin main ribs arranged by the ttomb store, ami 
them, downwards to the landing gear. The rear spar of 
the upper plains is also provided with a cable to the 
fuselage between the c.ibane and .strut. 

Tin- stampings for the fixing of the wiring is constructed 
\.-ry simply. A bent sheet metal of L' form and with 
drilled holes for the bolts carries the nipples of the eye- 
bolts. 

The Fuselage 

The canvas-covered body consists almost exclusively of 
aluminum tubes that are riveted with welded steel tube 



si. .MX : i|.l spanned with wire. Onh .it >p. i-ially stressed 
points in the front part li.-uc steel tnU-s In i n einployi-d. 
Tin up|K-r and lower sides of the 1 i . inded 

b\ the eiii|ilo\ment of fairings. 

The . iimn. r. s|> on aliiminiim I In -an rs that art- sup 
ported ly ri\eteil aluminum struts. Two pairs of large 
\iew trips an prox ided U-low the seats of tin- pilot and 
olisericr. and are operated by cable by tin obs. rvi r. 

The Undercarriage 

The \cr\ stroiij; landing gear has three pairs of struts 
of aluminum streamline tubes, strengthened \>\ 1 irons 
riveted in. and resting In low on hori/.ontal steel tubes. 
Tin- wheel shaft rests in an auxiliary one of steel sheet 
in t shape welded on. The back root points of the strt:ts 
are connected by means of a second steel tube auxiliary 
.shaft, welded on, and liy a tension hand lying behind. A 
diagonal wiring is further provided hori/.ontally in tin 
auxiliary shaft level. The streamlining of the shafts is 
cut out in the middle behind the front auxiliary shaft to 
improve tin sight downwards. There is only a diagonal 
wiring to the fuselage in tin level of the miilill. struts. 

The ash tail skid hangs in rubber springs from the 
fuselage and is strengthened in the rear end by a con-r 
ing of a rectangular aluminum tube. Its wire stay is sup 
ported ill the rear stem by a spiral spring. Leaf springs 
are further fixed to the end of the skid. 

Tail plane, rudder and elevator are of welded thin steel 
tubes. 

The aeroplane is equipped with complete dual control. 
The control in the observer's cockpit can IM- removed. 

The ailerons are interconnected. The twin control 
<'alil.s run behind the rear spar of the lower planes to 
two direction changing rollers resting on a shaft. Here 
they part and are led as separate wires of thickness of 2 
mm. to the underside of the aileron. In the upper plain s 
the ailerons are connected by control cables, governing 
two levers ill each side. The ailerons are balanced and 
welded to a common shaft. 



' 




A squadron of l-'rcndi Hrejruet bombing machines 



130 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



LIFt BOAT FORMING FAIRING 
OF FUSELACE. WHICH CAN ' 
tO. INSTANTLY, RELEASED 
FROM. -. PILOTS SEAT 



COCKPIT FOR PILOT 

AND NAVIGATOR 



375 HP ROLLS ROYCt 
"EAGLE." ENGINE 




PETROL TANK CAPACITY 
ABOUT 400 GALLONS FOR 
25 HOURS FLIGHT 



ENGINE EXHAUST PIPE 
TO ELIMINATE RISK 
OF FIRE 



The Sopwith biplane, in which Harry Hawker attempted to fly across the Atlantic 



The Sopwith Machine 

The Rolls-Royce engined Sopwith transport type spe- 
cially designed for crossing the Atlantic, is of the vertical 




Scale plans of the Short and Sopwith transatlantic type aeroplanes 



liplane type, the wings having no stagger. Pilot and 
navigator are seated well aft, so as to give a large space 
in the fuselage between them and the engine, in which to 
fit the large petrol tank required for the great amount of 
fuel that has to be carried for a 
flight of this duration. 

The cockpit of the occupants is ar- 
ranged in a somewhat unusual way, 
the two seats being side by side, but 
somewhat staggered in relation to one 
another. The object of this seating 
arrangement is to enable them to 
communicate with one another more 
readily and to facilitate " changing 
watches " during the long journey. 
The very deep turtle back of the fu- 
selage is made in part detachable, the 
portion which is strapped on being 
built so as to form a small lifeboat in 
case of a forced descent at sea. 

The Short Machine 

Fundamentally the Short machine 
entered for the race does not differ 
greatly from their standard torpedo 
carrier known as the " Shirl." It 
is a land machine fitted with wheels. 
In the place between the chassis 
struts usually occupied by the tor- 
pedo in the standard " Shirl " is 
slung a large cylindrical fuel tank 
which, should the necessity arise, can 
be quickly emptied so as to form a 
float of sufficient buoyancy to keep 
the machine afloat for a considerable 
period. In order to be able to 
carry the extra weight of fuel neces- 
sary for the long journey larger 
wings have been fitted, having three 
pairs of struts on each side instead 
of the two pairs fitted on the 
standard machine. 



SIX<;i.K MOTOKKI) AKKOIM.ANKS 



131 




The transatlantic flight type Martlnsyde hiplane at ! 

The Martinsyde Type 

Tin- machine is more or less of standard Martinsyde 
type, with tlir occupants placed very far aft to allow of 
mounting a large fuel tank in the middle of the fuselage, 
in the neighborhood of the center of gravity where the 




decrease in fuel weight as the fuel is used up will not 
alter the trim of the machine. In outward appearance 
it does not present any radical departure from the 
standard. It had the distinction of being the lowest 
powered machine in the race, the engine being a Rolls- 
Royce " Falcon " of 2H/i h.p. 

The general specifications of the Martinsydc are as fol- 
lows : 

Spun. l>th planes *3 ft. 4 In. 

Chord. Inith planes 6 ft. 6 in. 

Gap lietween plnnos 5 ft. 6 In. 

Area of main planes MM) &q. ft. 

Overall length -'7 ft. 5 in. 

Overall heiffht 10 ft. lo in. 

Fuel capacity 373 gallons 

Cruisinir radius ->.ooo miles 

Speed 100 to 1 m.p.h. 

Captain Frederick Philips Raynham, the pilot of the 
Martinsyde aeroplane, went with the Martinsydes in early 
development days in l'.K)7 and was with them when they 
began monoplane production in 1008. When the war 
began Martinsydes turned to building biplanes and the 
present machine is but slightly modified from their latest 
fighter. The machine for the transatlantic flight was 
taken from stock and still carries its original equipment 
such as used during the war. 




The Martinsyde "Hayntor' 



132 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 





FRONT ELEVATION. 




SIDE- ELEVAT.ON. 
Line drawings of the Grahaine-White Aero Limousine equipped with two 210 h.p. Uolls-Hoyce motors and tractor propellers. 



Grahame- White Aero Limousine 



The machine accommodates four passengers and a pilot, 
the latter in a separate compartment behind the pas- 
sengers, who have a perfectly clear view forward, down- 
ward and sideways. The limousine body is as luxuriously 
equipped as a modern interior-drive motor-car, and is 
equally commodious. Unsplinterable glass windows, both 
wind and draught proof, are fitted, and it will no longer 
be necessary, when using such a machine, to clothe one- 
self specially for flying. The limousine has a heating ap- 
paratus, a ventilating system, and a speaking tube connects 
it with the pilot's compartment. A specially-designed 
system of maps, under the control of the pilot, indicates 
to the passengers at a glance, and at any time, their exact 
position during a cross-country flight. The raised posi- 
tion of the pilot ensures him a clear outlook, and he is 
ideally situated for controlling both the machine and mo- 



tors. The two 270 horse-power Rolls-Royce motors are si- 
lenced as effectually as is the engine of a car. The use of 
two motors, either of which is sufficient when running 
alone to maintain the machine in flight, eliminates almost 
entirely the risk of a forced landing. The machine has a 
speed of 105 miles an hour, and will fly in anything up 
to a 4.0-miles-an-hour wind in perfect safety, and without 
discomfort to the passengers. With the motors throttled 
down, an easy touring speed of 60 miles an hour can be 
maintained. The four-wheeled chassis, designed on mo- 
tor-car lines, gives a maximum of strength and efficiency, 
and is fitted with special brakes which bring the machine 
quickly to a standstill on landing. It will also rise from 
the ground after only a very short run. The wings fold 
back, as shown below, to reduce housing space. With 
wings folded the span is reduced from 60 feet to 29 feet. 




The Farman " Aerobus " being used in the Paris-London passenger service. Two Salmson engines are used. Note the wing end 

ailerons. 



SINCJl.K MOTOHKl) A KK( )!'!.. \.\KS 



The German Gothas, the Aviatiks and the Ago biplanes 





Goths G2 




THE H. and M FAR.MAN 



FIGHTING AEROPLANE 




134 



SI.NU1.K MOTOHKI) AKKOl'I.AM ^ 



Ii 
I I 




Scale drawing, with dimension', in niilimrtrr., of the Type 17 Nii-nport M-out 

The Nieuport 1% Plane* 



An immediate step in the transformation from the mono- 
Jam- to the biplane is formed by the biplane with a larger 
op plane and a smaller bottom plane. This type, pro- 
Itici-il liy tin N import firm has speed and ease of handling. 
I'hii-li is characteristie of the monoplane, and stability and 
liort wing span, which is found in biplanes. 

Tin- N imports may be divided into three main types 

Pyp<- 11, a single-seater with rectangular body up to the 

nginc cowl, and the eowl covering the upper end of the 

notnr only; Tyjie 12, which is a two-seater, having its V 

nti rplane struts sloping outward, toward the top. 

!n this type tin- top plane has a fixed center section and i.s 

vercd with transparent Ccllon sheets to give a better 

The power is provided by a 110 h.p. Clerget en- 

tin. . The observer sits behind the pilot. The Type 17, 



of which we give here a line drawing, is a single-seater, 
with a circular front section, and some of this tyjie have a 
spinner over the propeller boss. The general arrange- 
ment resembles that of the Type 11. 

The ailerons are mounted on steel tubes, inside the ring 
and running along the back of the rear spar to the body. 
These tubes are operated from the control lever by means 
of cranks, pull-and-push rods and a crank lever. The 
(ranks are hollowed out to provide clearance for the rear 
spar. The top plane has slots cut in it for the cranks. 
The pull rods are connected to the crank lever by ball 
joints. The hand lever and the rudder pedal are the kind 
usually used. 

The top of the rear portion of the body is covered with 
curved veneer. The tail skid is supported on a structure 



136 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Xieuport scout aeroplane flown by American airmen in France. It measures only 15 meters from tip to tip, and is driven by 

a Hit) horse-power Gnome motor and a French propeller 



of veneer projecting down from the framework of the 
body. 

The machine-gun is rigidly mounted over the center of 
the body, directly in front of the pilot. 

Herewith are the dimensions and weights of one of the 
Nieuports: 

The Type n Single Sealer 

Span, upper plane 24 ft. 8 in. 

Span, lower plane 24 ft. 3 in. 

Chord, upper plane 3 ft. 11 in. 

Chord, lower plane 2 ft. 5 in. 

Overall length 18 ft. 10 in. 

Height 8 ft. 1 in. 

Area, upper plane with ailerons 97 sq. ft. 

Area, lower plane 49.5 sq.ft. 

Area, rudder ; 6 sq.ft. 

Area, ailerons 14 sq. ft. 

Area, stabilizer 11 sq. ft. 

Area, elevators 14.5 sq. ft. 

Stagger 2 ft. 3 in. 

Dihedral, upper 179 

Dihedral, lower 174 

Sweepback 170 degrees 30 min. 

Incidence, upper 1 degree 30 min. 

Incidence, lower 3 

Power plant 80 h.p. Le Khone 

Propeller, diameter 8 ft. 2 in. 

List of Weights 

Upper plane with fittings 79 Ibs. 

Lower plane with fittings 33 Ibs. 

Tail plane 7.7 Ibs. 

Elevators 9.5 Ibs. 

Rudder 6.6 Ibs. 

Body with engine, complete 583 Ibs. 

Wire stays '. 7.7 Ibs. 

Wheels 22.4 Ibs. 

Interplane struts 11 Ibs. 

Gross weight, empty 760 Ibs. 

Pilot 176 Ibs. 

Gasoline (20y, gallons) 121 Ibs. 

Oil (5 gallons") ..'. 44 Ibs. 

Machine gun and ammunition 110 Ibs. 

Useful load 451 Ibs. 

Total weight, loaded 1,210 Ibs. 

The climb in 4 minutes is 3300 ft. ; 7 min., 6600 f t. ; 11 



min., 9900 ft; 16 min., 13,200 feet. The lift loading o 
the machine per sq. ft. equals 8.3 Ibs., and the power load 
ing, 12.1 Ibs. per h.p. 

The propeller is a Levasseur, of 2500 mm. diameter an< 
a blade width of 270 mm. 

Comparative table of the three above mentioned types 

Xo. 11 Xo. 12 Xo. 17 

Le Rhone, 80 Clerget, 110 Le Rhone, 11 

7,520mm. 9,200 mm. 

7,400 7,460 

1,200 1,820 

700 900 

13.65 sq. m. 22.2 sq. m. 



Motor 
Top Span 
Bottom Span 
Top Chord 
Bottom Chord 
Total Area 
Incidence, Top 



8,300 mm. 

7,800 

1,230 

730 

15.6 sq. m. 



1 deg. 40 min. 2 deg. 30 min. 2 deg. 30 mir 



Incidence, Bottom 3 degrees 3 deg. 30 min. 2 degrees 




View of the forward end of a Xieuport, showing the cowlin| 
completely surrounding the motor, which distinguishes thi 
Type 17 




Sl.\(;i.K MOTOHKl) AKHOl'I.ANKS 



i:J7 



ii|>orl Scout itli twin l.rwis guns ami lixnl \'ickrrs gun 




A I'M-. I r, i,rl, Xiruport S.-..iil in flight. 



\ import Hipl.-me rqtiipprd with a 
( 'Irrupt motor 




Testing out a 120 h.p. I.T Rhdnr motor on 
I '. meter Nieuport ty|- J~.\ 



138 TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Side view of the Salmson biplane, equipped with the Salinson motor 




A French Salmson biplane. Two seated, it is used for artillery observation and contact patrol 




A Salmson biplane with a 250 h.p. Salmson stationary radial motor 



SI.M.I.K MOTOR Kl) A KRO1M.A M .S 



l.T.i 




III. I 'rent h Spml liiplunr i-<|iii|>|>cd with Ilispiino-Snizii motor 

The Spad Scout, Type S VII 



is type of plane has been used by many of the best 
Allied a\ i itors. 

.\pprii\iiii.-iti- general dimensions of the S VII are as 
follow - 

Span, uppi-r pliine (7.800 metres) J.> ft. (i in. 

Span, lowt-r plane .'."> ft. li in. 

Chord. Inith plane. (1.4IHI metres) 4 ft. 7 in. 

ll.-ip Ix-twn-n planes ( l.-'.'.'i meters) 4 ft. -' in. 

llvrrnll length (li.KHi meters) 90 ft. in. 

T( n I weight ... I/)- 1 .'. Mis. 

I...-K! 47(1 lli>. 

I Mini, in 10 minutes 9,100 ft. 

Sperd nt sea level lit.' m.p.li. 

t :(.("> n*T>rs I .'h m.p.li. 

fltta V tjpe Ilio h.p. 

Both pl.-itn s are nearly rectangular in plan, the i-nds 
U in;; si|ii in .-mil not rnkcd, with eorncrs slightly rounded 
off. Tin deep eut-out portion of the top plane, over the 
pilot's seat, as well as the elose spaeing of the intcrplane 
struts, shows a large area of plane surface aft of rear 
wiii In .mis. As the ailerons arc comparatively narrow, 
nist IK' carried on a subsidiary wing spar located 
about 9 inches back of the main beam. 

It will In- iidtii-rii that tin- iiiti-rpl.-iin- bracing is iiiiiisu.-il : 
's from each side of the fuselage extend directly to 
i struts, crossing at the intermediate struts. Where 
rea i ross tin-re is a steel tube brace connecting the 
.1 with rear intermediate wing struts. 



The fuselage is exceptionally deep, and the bottom is 
curved In-low the lower longerons as well ax the sides and 
top, giving a smooth streamline effect. The fore end of 
the machine, which house* the motor, is covered with 
aluminum, with a circular radiator opening which n -. m 
blcs the cowling of a n>t.-iry motor. I'rotulioranccs on 
cither side of the cowl show where the camshaft covers 
of the Hisp.-ino Sui/.-i motor project. Perforations are 
made in the cowling, about the motor projections, for the 
admission of air. 

The rudder is hinged at a point about 1<> inches Ix-yonil 
the fuselage termination. The usual fixed sUibilixing 
plane and elevators are employed. The vertical fin ex- 
tends 12 inches forward of the leading edge of the tail 
plane. 

Wheels of the landing gear have a track of 5 feet; the 
axle runs in slots which guide it up and backward in line 
with the rear chassis struts. Shock absorption is with 
rubber cord. 

The Hispano-Suiza motor develops 1GO h.p. at about 
1500 r p.m. Eight cylinders arranged V type, water- 
cooled, four-cycle, 4.7245-inch bore by 5.1182-inch stroke; 
piston displacement, 718 cu. in. Wright, including car- 
buretor, magnetos, starting magneto, crank and propeller 
hub, but without radiator, water or oil and without ex- 
haust pipes. 4-15 Ibs. Fuel consumption, one-half pounds 
of gas per horsepower hour; oil consumption three quarts 
an hour. 



140 TEXTBOOK OF APPLIED AEK' \V \ '1C ENGINEERING 




A French Spacl biplane. It is a single seater and Was used for pursuit work. It is equipped with two syn- 
chronized machine guns and is driven by a Hispano-Suiza motor of 320 h.p. 




Rear view of the 220 h.p. Hispano-Suiza Spad biplane 




A front view of the Spad biplane. Note the metal interplane struts, the " Eclair " propeller, and open cowl. 



SIM I 



W>KK1> .\KUUIM..\\KS 






I n 




Front \irw of (hi- Sp.ul I .111011 SIMJ, .s.-.ilrr. Knprir: .'.'n lip. 1 1 i-p.-uui Sni/.i. It li . n :t7 mm. (1 inch) cannon khootiiifr through 

UK- hull ul tin |irii| Hi i. .uul ..!-.. tun lixnl >\ uchronixeU gun* 




Siilr u 



Spud Cniniii Siiifrlr Sealer. ^.'0 h.p. Ilispnno-Suizn engini-. '|'|M- motor N completely eiu-knrd in the cowling. 
Tin- excellent >treainlinc shape of the fuselage can be seen from the photograph 




Spud 11-A3 Two Seater. Kn(rine: r h.p. I li-pmio -SuUa. 
I'M-I! t.ir ul -rvalinn pur|xM^. S|eed at 6i(K leet: II.' luili--- 
per hour. Climh to |li,VK( feet In :.' tniiiute'i. r'mliirnnce at 
gronn.l l.-v.-l: J hr-. l.i inin. Arm.imrnt: one stationary (fun 
ami -' flexihle gunv Crew: one pilot and one oliM-n.-r. 
l-'ipiipiiH-nt: Radio iind camera 



SKETCH OF BRISTOL SCOUT 



WITH Ls RHONE ENGINE 





J 

mm 




< CO 
? Q 

i < 

CL 



uj 




142 



SINCil.K MOTOKKM A I .!{< )IM.A\ KS 



WITH LeRHQME C NO INC 




Bristol Scout 80 Le Rhone 



Tin- Bristol Scout was adopted by the United States 
Army for .idv.inrrd training in 1918-19. 

ti of tli<- Bristol Sc-out at Wilbur Wright Field gave 

th. follow in_- results: 

.-d (ft.) M.p.h. R.p.m. 

i, ., , I.... - 

MM -'. M15 



Cli.nl. (ft.) 
10,000 



75 

Time 

1 1 ruin. 45 rc. 
.M miii. .' nee. 



1.170 

Ratr (ft.) 
tin 
240 



Srnirr orllln^ (climb 100 ft. per m!n.) 13.000 ft. 

Wright, rtnpty 7f MM. 

Total ICMI! 2M BM. 





Bri-tol Scout with 80 Lr 



Bristol Scout with M \JT Kh6nr 



144 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




TOP VIEW 



U5B-1 FIGHTER WITH 3OO H.P HISPANO - SUIZA ENGINE 



U. S. B.-l British Fighter 



300 Hispano-Suiza U. S. Army Tests 



Summary of Results U. S. B-i 



Useful load 




724 Ibs 




Fuel and oil 




. . 344 Ibs. 












Total weight 




3,910 Ibs. 




Pounds per sq. ft.' 




. . 7 05 




Pounds per h.p 




9 7 




Gasoline consumption 








Oil consumption 


g 




. ," 








,llSJ 


Climb (ft.) Time R.p.m. 


Speed 


H.p.m. 







114.5 


1,760 




6,000 5 min. 35 sec. 1,600 


113.fi 


1,700 




10,000 10 min. 45 sec. 1,600 


109.5 


1,660 




15,000 19 min. 30 sec. 1,600 


101 


1,600 




Theoretical ceiling: . 




. 25.000 ft. 





' 




U. S. B-l with 300 Hispano-Si iza 




SINCil.K MOTOKKI) A KKO1M.A M .S 




FRONT VIEW 




USB-I FIGHTER WITH 3OO HP HISPANO- 5UIZA ENGINE 





I S ll-l with :>0 Mi-|).n;i>-Si i 



Marlin-yilc Scout with :KI IlispiiiiD-Siiir. i 




llrixt.,1 Smut with -i) l.i- Hhoni- 




ISrisl.il So.ut with 



146 TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




FRONT VIEW 




U.5.B-B FISHIER WITH E9D H.R LIBERTY ENGINE 




U. S. 15-.' with I.ilicrtv "8' 





U. S. H--' with Liberty "S" 



crz 






U. S. B-2 with Liberty "8" 




S. B-2 with I.ihi-rtv 



SIXiJI.K MOIOHKI) .\KK01M. \\ I ^ 



147 





Martln&yde Smut \vit 



M.irt. ml with :VM> 1 Iis|>;iiici-Sui 



Martinsyde Scout 300 Hispano-Suiza 

Summary of Trials (British) 

Duty - - Fighting. 

Knginr Ilispano-Sui/a. .SO/i h.p., at 1800 r.p.m. 

I'n.p.-llrr- I). K. (i.l.. .V.J70. Din.. -'7 IO. Pitch, 2080 
(marked i. DI.I., U 

Military load 281 11>- 

Total Wright, fully Inadril 2289 Ibs. 

Ui -ight |IT s<j. ft. (i.ii:. Ibs. 

Weight prr h.p. 7.5 Ibs. 

M.p.h. 

Sprr.l at 10,000 ft H.'.:, 

Sp-.-.l at l.J,(HX) ft 136.5 



Greatest In iylit n-aclird 24,700 ft., in 37 mins. 
Rate of climt> at this height 1 10 ft. mill. 
Air i-inliir inr. . almut 2'/4 ''rs. at full speed at 15,000 
ft., iiu-luiliiiir climb to this height. 



Anrroid 

II.,,. I, I 



Radiator Temperature Readings on Climb 



Atmox. 



K nl 



Temp. C. Temp. C.' AoiX 



Miu. Sec. 

Climb to 10,000 ft.. 6 40 

Climb to 15,000 ft.. II 45 

Climb to ->0,(K)0 ft.. 19 40 



R.ofC. in 

ft. mill. 

1,176 

850 



R.p.m. 

I.-." 

1,795 



5,000 
IOJOOO 



IQflOO 



li 

7 


_fl 
18 



-s 

n 
ra 

7:f 



77 
74 



Pos. of 

K.p.m. HlimU 

l.i,.l" Oprn 

UlM 0|irn 

1,610 lip, i, 

l.vi-, i |.... .1 
1^75 



I.8.S. 

70 
65 
60 



H.p.m. 
1,610 
I. vi-, 
1,570 



SiT\icr ri-ilinjr (height at which rate of climb is 100 
ft. min.) a-l.-SOO ft. 

Kstimatcd absolute ceiling 26,800 ft. 



Oil Temperature Readings on Climb 
Starting with nil tank full. Castor oil, 4 gallons. 
Aneroid \tmnv Oil Kiipine Oil I'n-Mirr 

llriftht Temp.C." Temp. C." Trmp. C. lb./q. ft. 

(J.iMHt 6 60 74 75 

10,000 " 75 78 70 

H.OOO 7 85 80 65 

16,000 9 90 80 60 




TOP VIEW 



U.5. B-S FIGHTER WITH B9D RR LIBERTY ENGINE 



148 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




SEA 402. Engine: Lorraine 390 h.p. Two Seater Pursuit Biplane. Speed at 6500 ft.: 129 miles per hour. Climb to 17,000 ft. 
in 21 min. Crew and armament: Pilot has two fixed guns. Gunner has two flexible guns. Endurance at ground consump- 
tion: 2 hrs. 30 min. 




Hunriot Dupont HD 3-C2. Engine: Salmson 270 h.p. Two Seater Pursuit Biplane. Speed at 6500 ft: 128 miles per hour. 
Climb to 16,500 ft. in 25 min. Crew and armament: One pilot with two fixed guns. One gunner with twin flexible guns. 
Endurance at ground consumption: 2% hours. 




Side view of the Hanriot Dupont HD 3-C2 with Salmson 270 h.p. 

motor 




Side view of the SKA 403 with Lorraine 390 h.p. motor 




tl 

* 



> 

-i 

? 



X 
/ 



u 

X 



,1 




150 



SIN(;i.K MOTORK1) A KKOl'l ..\ \KS 



151 









1**" 



\nirricjin S. K. ."> with 1 s * > I li-jniici Sui/a 



The English S. E. 5 Single-Seater Fighter 



This biplane li.-is i surface of 't.H si|iinrc metres, and 
both |il:iiii-s. connected with hut our pair of struts to each 
.sidr. II.-IM- a span of K.l.'i metres, and a chord of 1.5*2 
metres, the gap I'niin tin' top of the fuselage amounting to 
41. ' :. mrtrr. 

rrow shape prevails. Tin- V shape* of tin* rqual- 
.si/.rd rnds of the upper and lower planes mounted on the 
centre section and respective body rudiments amounts to 

1.7 I tlejirei |, 

The siirlit field is improved hy cutting the centre section 
in the middle and the lower planes near the body. 



.\lio\e the aniile of incidence is 5 deg. mean, below by 
the hod\ li dt ir., by the struts 3 deg. 

Both plnnc .spars show sections of I shape, wl 
the longerons are steel tuln-s of 1.7.5 millimetre thicki 
and 1.5 mm. outer diameter. 

There are no compression struts between the spars. 
MMMI of the ril;s being solid struts instead. 

The interior wiring of the planes between the body and 
the struts is carried out in simple profile wire, that of the 
overhanging ends of thick -ended wire. 




5--5 PLANE WITH HISPANO-SUIZA ENGINE 



152 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




TOP 1//EW 

S-E-5 PLANE WITH H/SPANO-SU/ZA ENG/NE 



A wood strip forms the back edge of the planes. Fur- 
ther, two auxiliary ribs ranging from the leading nose edge 
to the main spar are arranged between each two ribs. 

The fabric is sewed together with the ribs, and is 
painted yellow below, browned above, as is the fabric of 
the body. Shoe-eyes are arranged on the underside of the 
trailing edge of the plane to assess the pressure. 

The centre section struts are covered steel tubes. The 
plane spruce struts rest in long stampings, serving as fix- 
ing points of the vertical wiring. 

Profile wire is employed for the plane cross wiring 
with twin wires for those carrying load and single for the 
counter ones. 

The two spars of the upper planes are strengthened 
further between the centre section and the struts with two 
wires each. Unbalanced ailerons are hinged to the back 
crossbar of the upper and lower planes. 

The body shows the usual strut and wire combination, 
being rounded above with half-circle frames and fairings, 
and having three-ply wood planking of 4 millimetre thick- 
ness to the pilot's seat. Fuselage longitudinals and struts 
have sections of I-shape, except the vertical struts behind 
the pilot's seat, which are worked out round. 

The tail-plane is curved to both sides and fixed to the 
body, so that the angle of incidence can be varied during 
the flight within the limits + 4.5 deg. and 3 deg. To 
this end the front spar is turnable, while the rear spar, 



with its wiring, is fixed to a tube, arranged shiftable to the 
body stern post. This tube rests with a piece of thread 
in a gear-nut, again resting in the stern-post fixed, yet 
turnable. 

When the nut is turned from the pilot's seat by means 
of wheel and cable, the tube is displaced upwards or 
downwards, transferring thereby the same manoeuvre on 
the rear spar of the tail-plane, and thus its angle of inci- 
dence changes. 

The elevator hooked to the fixed tail-plane partakes in 
this movement. The wires for operating the elevator are 
led through the body and tail-plane, which certainly saves 
air resistance, yet makes twice a 20 deg. direction change 
of each wire necessary. Main and tail-planes are equipped 
with cellon windows, rendering a control of the rollers 
possible. 

The under-carriage shows the normal form. The 
through-running axle rests between two auxiliary ones, 
There is no limit of the springing range. 

The tail skid shows an unusual construction, being ar- 
ranged turnable behind the stern post and connected with 
the rudder cable by intermediance of springs. A brass 
skid bow is sprung by means of two spiral pressure springs 
which are prevented from sideway turning by inserted 
telescope tubes. 

According to the firm's sign board the Wolseley-His- 
pano-Suiza engine gave the 30th August, 1917, on brake 



SINCil.K MOTOKKl) A I .!{( MM \ \ 1 - 



1 :,: 



.mi h.p. -.MLS I'.S. .it -.MIII.-, revolutions. Tin- r.p.iu. of 
tin- fi>nr hladi d airscrew is i;eirid down in tin- ratio ot 
I- to .'I. 

'I'lir exhaust gas is li-cl behind tin- pilot's seat in two 
tulics to i-.-icli siilr ot tin- hodv . Tin- motor sits so that 

thi-rr is (fit :i,-( -i ssilulity al'ti-r removing tin li. ct. The 

r/iili itor forms tin bow of tin- I odv . 

A i-oM-r amm-emi-nt makes it possible t<> uncover the 
body alioiit halt way from tin pilot s - 

Tin- main prtrol tank of IJH litre-.' capacity is | 
lu-hiiul tin motor on the upprr tusi-laii 1 ' longitudinals. A 
gravity tank of 17 litres capacity is arranged in the centre 
section between the li ailiim nl-t .mil the main spnr. Tin- 
oil tank of a capacity of I 1 litres lies cross in the engine 
frame below the nar eil^e ot tin motor. 

The fuel sullices Idr a (light of about two hours' dura- 
tion. 

Following instruments are -irmi^d in the pilot's seat: 

To right: A ho\ for the light pistols; a contact breaker 
for the self -starter ; a contact breaker for tin- two mag- 
netos; a triple led cock for the gravity ami pressure petrol; 
it triple led cock for the hand and motor air pump; a 
thermometer for the water of the radiator; the petrol 
gauge placed on the hack side of the main tank, and a 
m inoiiicti r for air pressure. 

To left: das lever; lever for regulation of the gas in 
altitude (lights; lever for operating the radiator Minds, 
clip for three light cartridges. On the lottom is further 
arranged a hand pump for the hydraulic machine-gun gear; 
two IIOM-S tor drums for the movable machine-gun and the 
sell starter. 

A .square windshield of Triplex glass is placed in front 
of the pilot's seat. li. hind it a box is arranged in a queer 
position to the body with access from outside. 

The ti\ed Vickcrs' machine-gun lies to left of the pilot 
inside tin- hodv fabric. The cartridge girdle is of metal. 
Tin- tiring of the machine-gun takes place hydraulic-ally 



bv mi-ana of a control arrangement, placed in front of tin- 
motor and connected with tin- in >. Inn. -mi through a cop 
per main, as well as driven from tin air screw bv a gear 
set. The firing lever sits on the stick. 

On the bow slnpi-d iron band lying on the centre ec- 
tion rests a Lewis gun. which can In- pulled down during 
the Higlit to permit vertical tiring. 

The empty weight of the a. roplanc was worked out at 
TOO kilos, distributed as follows: 



Kilos. 

3.6 

il o 



Knjrinr 

|-'.\li.nis| e.illn-tiiili 

Self-starter .... 

;T 

Itiiiliiitnr water ... 

Air screw M.6 

Main petrol tank 17.H 

('rnvity |x-trol tank 6.4 

Oil tank 

Mut.ir e<|iiipiiM-nt 6.4 

Bixly with M-at ami plate rovers 141.0 

Tail plate iiiijile of im iilener ehaiiftr arrangrmcnt 1.0 

I 'nder carrinjfr 40.8 

T,,il skid 3.7 

I'ilntiipr arrangement 4.4 

Planes with wirimj lli.3 

Vertical and horizontal wiring il.O 

HcMlv equipment " 14.0 



;,.., 

The fuel weight amounts with fully loaded tanks to 1 1 1 
kilos, so that the total useful load can be calculated at 
250 kilos, the total weight working thus out at '.>:>< kilos: 

9.16 
The load of the planes is thus: =12 kilos per 






square metre. 

The performance load Is then: 
horse-power. 






!.> kilos per 




Tail plane incidence gear of the S. K. 



154 

' 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 





^^IBH^^HHIH . - < i 

American S. E. 5 with 180 Hispano-Suiza 

S. E.-5 180 Hispano-Suiza 

BRITISH TRIALS 

The American machine of this name completed its tests 
under U. S. army supervision in 1918. 

For comparison, the summary of results on the British 
and American S.E.-5 is- given, as determined at Wilbui 
Wright Field: 

Summary of Results S. E.-5 (British) 

Climb (ft.) Time Rate R.p.m. Speed R.p.m 

1,170 123 2,100 

6,500 6 min. 50 sec. 810 1.800 118.5 2.080 

10,000 11 min. 34 sec. 615 1,800 115.5 2,040 



American S. E. 5 with ISO Hispano-Suiza 

Climb (ft.) Time Rate R.p.m. Speed R.p.m. 

15,000 21 min. 20 sec. 340 1,800 10T.5 1,965 

20,000 50 min. IT sec. 60 1,780 85 1.S20 

Service ceiling 19,400 ft 

Total weight 2,051 Ibs 



Summary of Results S. E.-s (American) 
Climb (ft.) Time Rate R.p.m. Speed 





6,500 
10,000 
15.000 
20,000 



8 min. 
13 min. 

22 min. 10 sec. 
min. 30 sec. 



750 
590 
350 
140 



1.800 
J,800 
1.800 
1,790 



121.6 
120 
117 
109 
92.5 



R.p.m 
2,100 
2,140 
2,080 
2,000 
1,860 



Service ceiling (where climb is 100 ft. per min.) 20,400 ft 

Total weight 2,060 Ibs 




A squadron of British aeroplanes, type S. E. 5 



M\(;i.K MOTOKKl) AKK01M.. \.\KS 



-MM 





I ...'. i. J\* Stxaitli.'inelMn 

Jfinyxan en <7)>an>r i 
f !** 



I ,. ..!' 

J. ^ t 1*1 c- *< 

^Ii x-x *. *. 



-*.r 



WlilllJ-lJ 




. .4 



ft V "" 







J,,< .. v . I 

- 



-WH- 



.'. '/- W .../.- 




X ," - 






-36> 



w 













1 












I 


** <0O *.- tt 


*'/ 
> .., v ..4.^. 


- -. .'..-.I 


Q >/-./. 
j *( 


.>'> 
*.**' 


1 

I 


* 






*.. 








r.4 . O IS 


!'*** 


' . * . * 
* . .J* - 


V .>>--- 


--* . -* 

***-.'* 

/.*.'.; j^-t-t 





r 



ini."- "f tin- Supwith Camel, cquip|)f<l with 1:10 h.p. Clrrp-t iiu)tr 







A flight of Sopwllh "Camels" over a British 



156 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Three views of the Sopwith biplane called 
the " 1% Strutter." The fuselage is 
similar to that of the triplane. 



The British Sopwith Planes 

The Sopwith Aviation Company has turned out several 
models of fighting machines which have proven very suc- 
cessful. One of the best known types is called the "Pup " 
and possesses very great speed. It is a two-seated tractor 
and is frequently referred to as the 1 J /2 " strutter." Com- 
plete details of the Sopwith machines are not available at 
the present time. 

The motors used are the Clerget, Gnome, Le Rhone, or 
Gnome-le-Rhone. 

The Clerget 90 h.p. motor weighs 234 pounds, has seven 
cylinders with a bore of 120 mm. and a stroke of 160 mm. 
The 100 h.p. motor weighs 380 pounds, has nine cylinders 
with a bore of 120 mm. and a stroke of 160 mm. 

The overhead inlet and exhaust valves are mechanically 
operated, driven independently by two eccentrics a dis- 
tinctive feature; one crank, single and dual ignition, alumi- 
num alloy pistons. The crankshaft serves as an induction 
tube. 

The Le Rhone motors are built in sizes delivering 60, 
80, 110 and 150 h.p. at 1200 r.p.m. The 60 h.p. has seven 
cylinders, with a bore of 105 mm. and a stroke of 140 mm. 
It weighs 199 pounds. The other motors have nine cylin- 
ders. The 80 h.p. has a bore and stroke of 105 x 140 mm. 
and weighs 240 pounds; 110 h.p., bore and stroke 112x 
170, weighs 308 pounds; and the 150 h.p. bore and stroke 
124 x 180, weighs 360 pounds. 

The cylinders are turned from steel and fitted with cast 
iron liners. Cylinders screwed into steel crankcase. Two 
valves seating in cylinder head; induction via crankcase; 
shaft to crankease and two valves seating in cylinder head ; 
induction via crankshaft to crankcase and by external cop- 
per pipe to cylinder head. Forced lubrication. Consumes 
.72 pints of fuel and .1 pint oil per b.h.p. 

The Gnome 100 h.p. has nine cylinders; bore 110 mm., 
stroke 150 mm. Weighs 280 pounds. Fuel consumption 
nine gallons per hour. 




The Sopwith "Camel" 

The Sopwith " Camel " is a single-strutter machiiu 
and is a development of the Sopwith " Pup," from which, 
however, it differs in many details, apart from the greatel 
power of its engine. 

As in the older type, the wings and tail plane with ele- 
vator are of trapezoidal plan form, but the greatest spai 
occurs at the trailing edge. The top plane centre-sectioj 
has a span of 2.17 m., while the strut attachments are onlj 
1.48 m. apart. As the petrol pressure tank and gravitj 
tank are placed rather far aft, the pilot's seat is placed 
immediately behind the motor, underneath the top plane 
centre-section. In order to provide a better view, a recfc 
angular opening is cut in the centre section. The longa 
tudinal edges of this opening are provided with three-plj 
plates projecting beyond the wing profile so as to reducj 
the amount of air flowing over the edges. To facilitate 
getting into and out of the machine the trailing edge of thj 
centre-section has been cut away. Upper and lower pland 
have an equal span of 8.57 m., and an equal chord of 1.31 
m. The aspect ratio is therefore 6.25 against the aspi-ci 
ratio of 5.15 of the older type. 

The wing spars, which are made of spruce, are spindled 
out to an I section, with the exception of the bottom reaj 
spar, which is left solid. The gap between the planes h 
1.31 m. at the tips and 1.52 m. near the body. 



SINC.I.K MOTOUK1) A KK( )IM..\\KS 



157 



British 

Avro 

Aeroplanes 

The 15rili-.li Axrn Company has 

>eeii prolific in its production of 
yp's. Tin- characteristics of 

oinr of tlir lati-st t\ pi -. an- re 
>rodticed herewith hy courtesy of 
It-rial .li/t- II <</.///. 

Mr. A. V. Hoi was OIK- of the 
irst aeronautic engineers to pro- 
: triplanc which, it will ! 
ccallcd, Mr. Hoc him-clf Hew at 
In- historic Ho-ton I I.-trv.ird i\ii 
ion in. it in 1'MO. 

It will !.< recalled that tin- Hrit- 
sh Secretary of State for the 
<oy.il Air I orce. speaking at 
Manchester on December 20, 

IS, said of the Avro training 
lachines : 

It was uni(|ile evidence of the 
icrtection of the design of ... 
In- A\ ro that to-day it had bo- 
om, the standard tr.-iininj; ma- 
hine of the Hoy a I Air I-'orce and 
huilt in larger mimlxTs than 
ny otln-r Aeroplane in the 
orld." 




AVBO S3 1 A 



Side F.lcvatloni of Ib Awo Machlntn. 





Table of 


dimensions of Avro machines. 




TV-TV oi 


4 Wing 
pn. 


Vfmr 
chord. 


In.l,K 


rea oct " 

leio*l dncc. 




|j 


. 
I 


Dlhr.lr.il 


Am 

i 


\nt 






71 * 

nuKhm*- 


?. 















j 


S 


I 
1 








J 


_i 


3 










1 


I 


I 


i 


i i 


1 1 


I 


o 





1 


d. 
o 
t- 


i 


r l 


i-0 

Hi 


1 


'*' 


1 








ft. in. It. in 


it.i . 


It. in. 


It. in. 


, i i: - 1 


n. ' 


* 


II. HI. 


ll. in 









si-U. sji 


I1C f ITI 


| urr I.-. 1 






1Pff 


ll 11 16 


36 


1 10 


4 10 


171-5 15*3 


})o*o 


5 


3 6 


t z 




>*3 


- 


43' \ ;*> o 


||*C 


44-0 


O- 90 


00 






JJO 


39 So 
18 6 )6 


60 
} 6 


7 o 
5 


7 
S 6 


4i*o 397*0 
182-0 164*0 


(115-0 
346*0 


'O 

*o 


7 3 
5 


O 

1 9 




i J 
1-3 






- . . 


43*0 
13*8 


1JJ-0 
)2- 2 


17- 210 
4- 8-8 


13- '. 






)aoA 


n i 04 


ft 


7 6 


7 6 


463-0 445*0 


910-0 


o 


7 1 


o o 





3*o 




\ ?1 ' f* 4 s 4 






1 245 


34 ' ) 






Sp-M-rr " 
M,.o- 
cb*stcr 1 


B 9 


21 

6c 


6 

9 & 


t 6 
fi 


|6-0 46.-0 


>08-0 


o 


4 >l 


o 


| 


o-o 




Ji-o 13 j 


10-4 


2V6 


7 -t 


r'l 






Man- 


37 O OO 




/ o 


7 w 


















1 24 o 69*0 


38-0 


IO7-O 


16- tS-o 


J4-0 






Chrtn 11 


37 60 


60 


7 6 


7 6 


430*0 387*0 


817-0 


o 


7 j 








'i 


- 


1*4-0 3O-O 


33-0 


83-0 


It- 16-9 


18-0 






3041 


31 I 3 


36 


4 10 


4 10 


I7O*O |6O*O 


J10-0 


3 


3 


a > 


| 


*'i 




43-5 -"--o 


TS-0 


44*0 


6* 90 


13-0 






SJIA 


20 6 1 


27 


4 6 


4 6 


106 o 104*0 


210-0 


$ 


4 1 


x o 





10 




19-1 I7-J 


II -0 


J8-3 


O- 7-6 


7 S 






Pojni'ai-" 


1 S J 5 


*5 


1 


4. 


*>t-o Hj-o 


tlo-o 


M 


4 


1 4 





|*0 




27 ( < 


y 


: 


O '1 ? 1 


I 




Table of weights, etc., and performance 




Type of 
machine 


Engine. 


Weight of 
machine. 


1| 

u. g. 
3 


&! 


Speed 
(m.p.h.). 


( limb 
(in mins ) to 


I 

O 


f! 


f 


Load/h.p. 


P 






H.P 


K 


fl 


i 


'; 


It 


9 


| 


| 


| 









Type. 












. 


Q 


8* 






















finuis 






6~ 


- 






it 


m p h. 


Ibs. 


Ibs. 


b 






Rk(5>3) 


Le Rh. 

2 S. 


no 


1,230 
4.OOO 


1,823 
6.064 


3 

7 


225 

616 


9 
97 


75 
88 


65 


a 


-5 
J 


16 
7 


65 




35 
40 


5*5 2 
7*3 


16.5 
'5*9 








530*. 


H.S. 


200 


1.685 


2.680 


4 


432 


III 


108 






'. 




'4 


4t 


18,000 


45 


8-23 


'3*4 


'M 








2-H H.P. 


44<> 


4.361 


7. '35 


5**5 


< 


56 


11*6 


106 


93 


7 




'7-3 


35< 




45 


7*75 


16.2 


1.2)0 






Spider(53i) 


C. 


130 


063 




'.5'7 


3 


330 


130 


no 






i 




9-5 


22: 


19,000 


40 


7*78 


II. 6 


"5 






Manchester 


















































I 


2-D. 


640 


4.079 


6.586 


5 - 75 


700 


128 


122 


"5 


4 


; 


u 


4 


:oooo 


45 


8*06 


10*3 








Manchester 


















































II 


2 P. 


600 


4.574 


7.1 


=,> 


3-75 


446 


'15 


119 


I I : 


s 


6. 


- 


11.5 


43i 


17.000 


45 


8. 76 


*9 


1.074) 






5041* 


C. 


130 


1,408 


2,006 


2 


160 


80 


65 






1 


. 


*5 






4 


6.09 


18.1 








53'A 


C. 


130 


961 


l.5'4 


3 


330 


I2O 


i to. 5 


103 


4) 




9 5 


22: 


19.000 


40 


7.22 


IT. 6 








Popular 


















































(534) 


G. 


35 


607 


5 


844-5J 


3*5 


"7 


70 


67l 


621 


2O 








30 


4 69* 


>4 1.1 






I.e Rh. - Le Klione. S. - 


Sunbeam. H 


S. Hitpano uixa 


C - Ckrgei. D. ^ " .Dragonfly " A.B.C. 


P. - Siddcley " Puma. G. 


- Green. 


At lo.ooo ft. < 


To 18.000. J To 15.000. { To 


1 7.000. | At 3.000. f At 5,000. 




THE ITALIAN 5.V.A 

210 K> SPA MOTORED 

FIGHTING 5COUT 



CENTIMETIRS 



r ,'. 



M'Laajblj; 



158 



SIXCLK MOTOKK1) AKKOl'l \\KS 



l.V.t 




'I'hr It >li in > V \ I ifilitiii): Tractor equipped with a Spa iOO h.p. engine and provided with two Virkrrs machine jcun. This ma- 
him- ran clinil) 10,000 fret in H ininiitcs with a military load of 500 |M)iincls 

The S. V. A. Fighting Scout 



The S. V. A. machines arc manufactured by Gio. An- 

vildo & Co., of (icnii;i. Italy, in a nunilicr of types quite 

similar to one another, the principal differences being in 

In- wing spread and weight. In nearly all the types, the 

inn- |>ropi-lli-r, motor and fuselage is used. With the ex- 

eption of one of the types, the interplane strut bracing at 

itlu-r side of the body is arranged in the form of the 

-ttrr A'. The machine is convertible for water use by re- 

l.'irinif tin- landing gear with twin floats, as illustrated in 

lie photographs. 

All tin- material used in the construction of these MM 
hiiics is trsted in laboratories before being installed, and 
gain rigidly inspected when the machine has been tested 
ut in actual flight. The woods are tested for transverse 
nd longitudinal tension and compression, etc. Cables arc 
nun .s to Id times as strong as calculations show them to 
* nri-i-ssary under extreme conditions. The silk-linen 
o\ triii;; is somewhat transparent and after being treated 
vith dope is practically untearable. 

Tin- dimensions given below accompany the drawing 
hown. 

General Dimensions 

ipan. upper plane 9.100 mm. (30 ft. 3 In.) 

ipan, lower plane 7,600 mm. (25 ft. in.) 

'honl, both planes 1,650 mm. (5 ft. 5 In.) 

1,800 to 1,500 mm. (5 ft. II in. 4 ft. 11 in.) 

Krrnll lenjfth H.100 mm. (i6 ft. 7 in.) 

Her .11 hei(fht 3^00 mm. (10 ft. 6 In.) 

ft'eijrht, emplj 640 kff. (1.411 His.) 

ijrht, loaded 900 kg. (1.9S4 UPS.) 

Motor, SI 1 \ ilO h.p. 

Maximum speed 33-3 km. (Hi ml.) p.h. 

Minimum s|>eed W km. (45 mi.) p.h. 

iTHmh in 14 min 4,000 met.-rs (i :,!.>: ft.) 

Main Planes 

The planes are in four sections. The top plane is a 
tl.-it span, but the lower plane sections are set at a dihedral 
Tin- wing curve has a negative tendency at the 



trailing edge, and the planes are given but a slight inci- 
dence angle or angle of attack. As in most of the fast 
Italian machines, the trailing edge is flexible, tending to 
flatten out the wing curve as the speed of the machine 
increases. A single set of ailerons are hinged to the upper 
plane. 

The steel-tube interplane bracing is of streamline sec- 
tion, and attachment to the swing spar is by a pin running 
through the end of the brace, parallel to the line of Might. 
The bracing method employed is such that both the lift and 
landing stresses are taken by the struts, eliminating the 
wire bracing cables. Drift and anti-drift cables are used 
in the usual manner. 

Main planes have a surface area of about -tl.'2:> sq. m.; 
the loading of the machine is about 36,7<M> kg. (about 81 
pounds). 

Fuselage 

At the forward end of the fuselage, the motor is en- 
tirely covered in. and the cowling runs back in a straight 
line as far as the pilot's seat. The rear curves of the 
under side of the fuselage are composed of a series of 
straight lines, and not a continuous curve. A noticeable 
feature of the fuselage is its narrowness in the vicinity 
of the tail plane, and its exceptional depth forward. 

The interplane struts sloping outward from the fuselage 
are not connected to the upper longerons, but are carried 
part way down the vertical spacing members between the 
up|wr and lower longerons. Evidently a compression 
member is located at such points, running from one side 
of the fuselage to the other. 

Veneer is used for covering in the body, except at the 
front end, where the aluminum cowling covers the en- 
gine. 

Tail Group 

The leading edge of the tail plane is located at the level 
of the center of propeller thrust, as indicated on the draw- 



160 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Official photograph. 
View of the body assembling and covering department of the Ansaldo factory, one of the largest Italian aeroplane factories 



ing by the dotted and dashed line, and the plane is fixed 
at a negative or depressing angle. It will be noticed on 
the plan view of accompanying drawing that the tail plane, 
or hori/.ontal stabilizer, is exceptionally small, its area 
l.eing only slightly more than half the area of the elevators 
or tail flaps. The flaps are worked with short control 
tillers located close to the body. A pair of steel struts 
support the tail from the fuselage. 

The familiar triangular fin OP vertical stabilizer is used, 
with the rudder hinged to its trailing edge. The lower 
end of the rudder is carried in a cupped metal fitting at- 
tached to the under side of the fuselage termination. 

Control wires run into the body through protective 
metallic plates with friction-reducing guides. 

Landing Gear 

Steel tube chassis members carry the floating axle, cross 
wired in the usual manner. The shock absorbing rubber 
elastic is covered in to reduce skin friction. 

The tail skid is unusual inasmuch as it relies upon a 
steel leaf-spring skid for its shock-absorbing effect. The 
upper end of the spring is rigidly clamped to a metal con- 
tainer, from which supports are run to the upper longerons 
of the body and to the tail plane. 

Motor Group 
The engine is a 6 cylinder SPA developing 210 h.p. at 



1600 revolutions per minute. The propeller is 2750 m. 
(about 9 ft. in.) in diameter, with a 2100 m. (6 ft. 11 
in.) pitch. 

Gasoline is carried for an endurance of 3 hours, weigh- 
ing 105 kg. (231.48 Ibs.) and oil weighing 15 kg. (3:!. 06 
Ibs.). 

General 

In the empty machine, the weights are distributed as fol- 
lows: Machine unequipped, 300 kg. (661.38 Ibs.) ; motor, 
propeller and radiator, 315 kg. (691.45 Ibs.); fuel tanks 
and the necessary piping, 25 kg. (55.11 Ibs.). Total 
weight 610 kg., or 1410.95 Ibs. 

The useful load consists of oil and gasoline weighing 
120 kg. (264.55 Ibs.) and an additional useful weight of 
140 kg. (308.65 Ibs.). The loading of the machine per 
b.h.p. is equal to approximately 9 Ibs. 

This type of S.V.A. machine is also manufactured in 
what is called the " reduced size," in which the wing span 
is shortened to 7570 mm. (24 ft. 10 in.) but otherwise lire- 
serving the lines of the " Normal " type. In the smaller 
machine, the total weight of the machine is 875 kg. 
(1929.04 Ibs.) instead of 900 kg., and the loading on the 
surface is 39.300 kg. (87 Ibs.) instead of 81 Ibs. as in the 
" Normal " type. With the smaller machine, the same 
powered motor, and a change in the angle of incidence of 
the planes, a much greater speed is obtained. 



SINCiLK MOTOKKI) A KKOI'l . \ \ I > 
The Pomilio Reconnaissance Type Tractor 



161 




I ili m I'liniilin ICi-i otiiiaissance ami llomliarilmcnt Arroplanr. \pparatu- i- r.irrird fur thr releitM 1 of honili-. mill n movahle 

iiiafliiiir-^nii h iiiiiiuilfil at th* rrnr ruckpit 




I: \i.'w <if Ih<- I'liinilii) Aeroplane. It has a 6-cylimler KM) h.p. Fiat cn(rfne and a Fiat marhinr-frun. \\"nif S|>MII. 
height, l'-"s overall li-ntflh, 30'-O" 




M- l-oiinlio Hrconn.nss,,,,-,- and Boml.anlmrnt Tractor s M-en from UK- M.lr. ()ffi.-ial lrst> |,ae shown Ihi- innrhine to Iw 
.hie of a horizontal speed of 1*0 miles an hour. Its rlimh is also very good, an ascension ..f 

.'.' minutes 



162 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Gravity 
Tank 




A.E.G. ARMOURED AEROPLANE 

Span 4*' 6' 

Chord S' 4* 

Gap V6' 

Tail Plane Span ' o* 

Overall Length 3' 7 f 

Engine (" Benz ") * 

Propeller- 'o 7 3* <lia 

Thickness of Armour 5 

Track 6" ioi 




SI\(.1.K MOTOHKI) AKKOIM.ANKS 



The A. E. G. German Armored Biplane 



This :u Toplanc is designed f,.r the purpose of carrying of which terminate in ball ends dropped into sockets, and 

out offensive patrols against iiif.-intry. and i-, furnished there bolted in position. 

with armor, which affords protection for its personnel. The centre section contains an auxiliary gravity petrol 

This armor appears, however, to be more or less expert- Unk, and also the radiator, ami is, therefore, substantially 

mental. braced with steel tube transverse members. 

In general construction it closely follows the lines of The wings are set with a dihedral angle of approxi 

the A. I 1 '.. <. Twiii Kngincd Bomber, though the arrange- mately 6 dcg. 

incut of the power plant is. of course, entirely different. Tin- aileron framework is of light steel tube through- 

A steel tulnilar construction is used practically through- out, the tube forming the trailing edge being flattened into 

*it an elliptical seetion. The ribs are fixed by welding. The 

The leading particulars of the machine are as follows: framework of the ailerons on the upper wing is reinforced 

by diagonal bracing of light tube. 

of upper wings 190.4 sq. ft. Tln-.se are of light steel tube streamline in section. 

of lower wings ... 168 sq. ft. tapered at each end, and terminating in a socket which 

Total MM of i,,^ ... 348.4 sq. ft. aDU ts against a ball-headed pedestal carried on the wing 

\n i ot up lie r aileron 11.9 sq. ft. , ., , . . ., . .. . 

A re. of lower aileron 10 sq. ft. "P" 1 5 thr U h ll)e 8Ocket " d the bal1 P"** 1 Sm " 

Area of tail plane 9.4 sq. ft. o\i. The manner in which this attachment is carried 

Area of tin 7.6 sq. ft. out is exactly similar to that in the A. K. (i. Bomber. 

Are i of rudder ... 6 sq. ft. The whole of the fuselage is built up of steel tubes 

Il,,ri/.,.nti.l area of iMKly . 48.6 sq. ft we , dcd io ^ titfr and , lavi , ffixed at their j unctions aheet 

.Side area of liodv 54.8 sq. ft. 

( r -,-tional area ,,f Unly 14.4 sq. ft. steel V *"* ve as the anchorage for the bracing 

.if side armor 33 sq. ft. wires. The diameter of the longerons and of the frame 

Area of Imttuni armor 29.4 sq. ft. verticals is 20 mm., except the last three members adja- 

.if armor bulkhead 10.4 *q. ft ^^ to tne tail, of which the diameter is 16 mm. The 

welding throughout the fuselage appears to be of very 

t rew pilot ami gunner 360 Ibs. 

Armament three guns. h 'g n quality. The longeron, from a point immediately in 

Petrol capacity 38 gallons front of the pilot's cockpit to the rear of the gunner'* 

Oil capacity 3 gallons cockpit, is fitted with a wooden strip taped in position. 

This joint shows the method in which the cross brac- 

Tlie manner in which the wings are constructed is ex- ing wires are furnished with an anchorage. In one or 
actly as shown in the A. E. G. Bomber i. e., the spars two points in the frame construction the bracing wire 
consist of two steel tubes -10 mm. in diameter by 0.75 mm. lies in the same plane as the transverse tube, and to allow 
thick. At their ends the upper and lower surfaces of for this a diagonal hole is drilled through the tube, and 
the spars are chamfered away, and flat plates welded in filled in with a small steel tube welded in place. 
position, so as to provide a taper within the washed-out This consists of a triangulated arrangement of steel 
portions of the wing tips. The wings were, unfortunately, tubes carrying hollow rectangular section steel bearers, on 
s.i badly damaged that no accurate drawing of their sec- which the crank chamber is slung. The bearers are well 
tion can be taken, but there is evidence that this very trussed both in the vertical and horizontal planes, and are 
closely follows the section of the bomber, which has al- shown in dotted lines in the General Arrangement Draw- 
re-idy been published. The ribs are of wood, and between ings. The engine bearers themselves are 2 mm. in thick- 
each main rim is placed a half-rib joining the front spar ness, and have an approximate sections of 2 1/16 ins. by 
to the semicircular section wooden strip which forms the 1 ' o in. 

leading edge. The wing construction is strengthened by The empennage possesses no particular points of in- 
two light steel tubes passing through the ribs close be- terest, the planes having the usual tabular framework. 
hind and parallel to the leading spar, which are used for The tail plane is not fitted with any trimming gear, but 
housing the aileron control wires. The bracing against a method of adjustment is provided. The diagonal struts 
dra- consists of wires and transverse steel tubes welded which proceed from the base of the fuselage to the tail 
in position. At the inner end of the wings special rein- plane spar arc fitted at each end with a method of adj list- 
forced ribs of light gauge steel tube are provided. The ment, allowing them to be extended as required accord- 
spars are attached to the fuselage by plain pin joinU. ing to the particular socket which is used to carry the 

The centre section of the upper surface is constructed leading edge of the tail plane. Neither the elevators nor 

in a similar manner to that of the wings, except that it is the rudder are balanced. The rudder post is mounted 

considerably reinforced, and the spars are larger in diam- on the end of the fuselage, so that the vertical frame tube 

etcr. The leading spar has a diameter of 51 mm. and the of the fin is very stoutly attached to the frame by a tri- 

rear spar 45 mm. The centre section is secured to the angulated foot 
fuselage by a system of stream-lined steel struts, the feet 





GERMAN AGO 

1917 TYPE -230ffBENZ 

FIGHTING 5IPLANE 



J'cale of fee( 

' i 1 i i i \=r=c. 



104 



McLaujUiii j 



SI.M.I.I. MOTOHK1) AKKUIM.ANKS 



Tin: \<;<> inn \\i 

Tn|i: Three-quarter front view. Tin 
opening in tin- top pl.mr for thr raili 
Jilur mill petrol serxiee tjnk should lie 
niiti-il. Itnttiiiii: \ i. fniiii jili.ue. 
shoxunjr in ilin|!raiiiiiijitic form tin- cnn 
slriictioii of top plane. IIIM-I: The 
t.iil 











(The German Ago 
8 regards its general lines, tlic Ago is of a striking 
unusual appearance, mainly, no doubt, due to the fact 
that its wings are tapered very pronoiitiredly from nmt 
to tip. This is very unusual in any modern, and when 
it is suddenly met with in a German machine of compara- 
tive recent date from various marks on tin- machine one 
gathers the impression that it was built certainly no longer 
ago than the first months of 1917 the question that 
first comes to mind is naturally enough related to the 
raiton d'etre of this uiiusu.-il design. 

In the first pl.-ice. it is ohvious that whatever it was the 

_ncr was aiming at. he was prcp.-ircd to go to consid- 
erable trouble to ohtain it. since the construction of sueh 

"d wings as those of this Ago are not by any means 

n attractive proposition commercially, entailing, as it 

the separate construction of half the ribs, no two 

> liieh arc alike from root to tip in one wing. Also 
M the spars converge to a point at the tip. they intersect 
the ribs at varying distances from root to tip. which again 



\ 



Fighting Biplane 

iiie.-iiis extra work in manufacture. Ax for the spars 
themselves, (hex also taper from root to tip. again more 
trouble and expense. 

When .standing in front of the machine one is at once 
struck by the peculiar bracing of the front spar. In- 
stead of the usual interplane strut there is on tin 
only a single solid wire running from the front lower spar 
to the front top spar, while no lift or landing cables of 
any sort are employed Ix-tween the two front spars. 

This feature, then, will probably IK- found to contain 
(lie solution of the peculiar design. By doing away with 
the front bracing, a much freer field of firing is obtained, 
and there can be little doubt that this was the object for 
which the designer was striving. 

Owing to the backward slop, of the leading edge of 
the planes, the outer inter-plane struts are farther back 
than they would be in a machine with straight wings, and 
also owing to the taper, closer together and therefore 
obstructing the field to a smaller extent. The narrower 



166 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Some constructional details of the Ago biplane. 1. Dimensions of lower front spar 
near body. 2. Attachment of tubular struts to fuselage longerons. 3. The hardwood 
distance piece at the crossing of the internal wing-bracing cables. 4. Section of the 
lower front spar at the point of attachment of the interplane wire. 5. Perspective 
sketch of same joint. 6. Section of rear spar. 7. (A) construction of false spar and 
aileron leading edge; (B) An aileron rib (not to scale); (C) Aileron crank and attach- 
ment of inter-aileron strut 



chord near the tip will result in a smaller travel of the 
centre of pressure, hence possibly the twist on the wings 
may become less, and the absence of front bracing be a 
less serious defect than one is inclined to imagine at first. 

When we say absence of front bracing, this is not quite 
correct, since, as already indicated, a single solid wire 
runs from top to bottom front spar. As is well known, 
in biplanes, with top and bottom planes of the same area, 
and with the conventional spacing of gap about equal to 
chord, the top plane carries about 30 per cent, more load 
than the bottom one, or roughly, 4/4 and 3/7 respectively. 
By running a wire from the top to the bottom front spar, 
the latter is therefore made to carry a certain share of 
the top spar's load, thus relieving, to a certain extent, the 
enormous bending moment that must be present on a com- 
paratively heavily loaded machine, whose front spars have 
a distance of some 13 ft. 6 in. between supports. 

So much for the general design of the Ago. As regards 
the construction there is much detail work that is inter- 
esting and unusual. The fuselage which is, as in the 
majority of German aeroplanes, of very roomy propor- 
tions, as regards occupants' accommodation, is covered 
with fabric except the front around the engine, which is 



covered in the three-ply. The floor of the fuselage is of 
three-ply from the stern to the gunner's (rear) cockpit. 
From there to the nose the floor is three-ply, covered 
with aluminum. In. section, the fuselage is rectangular, 
a light and comparatively flat structure forming a turtle 
back over the top of the main fuselage framework. This 
turtle back is built up as a separate unit, and is easily 
detachable by means of a neat and very simple clip. In 
case of severe stresses being put on the fuselage, it is 
therefore an easy matter to detach the top covering and 
examine and adjust the internal bracing. 

The four longerons, which are of square section, are 
pine, from the rear cockpit to the stern, while in front 
they are made of ash. The struts are in the form of 
steel tubes and the solid wire bracing is attached to the 
struts in the manner shown in one of the accompanying 
sketches. A small socket apparently machined out of 
the solid steel bar, has holes drilled in its edges, through 
which the bracing wires pass. This socket is slipped 
over the end of the tube, which has small dents in its 
end to give more room for the loop of the wire, and the 
socket, with its strut, is secured to the longeron by a bolt 
passing through it, with the nut and a spring washer in- 



SIXCLK MOTOKKI) AKKO1M.AM - 



KIT 



sitle tin- socket, as shown in section in mil- of our sketches. 
Kxcept for the fact that the longeron* arc pierced by two 
lioles the horizontal and vertical fuselage struts are 
.staggered in relation to one another close to one an- 
other, this arrangement appears to ! \rr\ neat, and cer- 
tainly takes up very little space. 

In front, the fuselage bracing is in the form of diagonal 
steel tubes, no wires bciii'j employed. The rear eoekpit 
is ivcupicd li\ th<- nrichinc gunner, who is seated on a 
small seat built up of a framework of steel tubing, over 
which is stretched canvas. This seat is .so hinged and 
sprung that immediate ly the gunner stands up the seat 
springs into a vertical position out of his way in case 
he wishes tu <lo his shooting in a standing position. When 
horizontal, the scat is supported by a slanting steel tube, 
pivoted at its lower end to the floor, and having its upper 
end running in a steel guide, bolted to the under side of 
the seat. The principle will be better understood by 
reference to one of the accompanying sketches. The gun 
is mounted on a swiveling bracket, which, in turn, is sup- 
ported on a rotatahle gun ring of wood, forming, in effect, 
a turntable, by means of which the gun may be traversed 
in any desired direction. To prevent damaging the nose 
of the machine and the propeller, a stop is provided for 
the gun in the form of two small frames clipped to the 
rear legs of the cabane, which prevents the gun barrel 
from travelling too far inboard. 

The pilot's seat, which is in the front cockpit, is placed 
on top of the main petrol tank resting on the floor of the 
fuselage. A service petrol tank is carried in and mounted 
flush with the top plane just to the left of the cabane. 
In the corresponding opening in the upper right-hand 
wing, is carried the radiator, and in connection with these 
two it is interesting to note that the water and petrol is 
led through the right and left cabane legs respectively, 
thus saving a certain amount of piping, which would other- 
wise be exposed to the air. 

The controls are of the usual German type, with a ver- 
tical lever terminating at the top in a double handled grip, 
and mounted via a universal joint on a longitudinal 
rocking shaft, having at its other (rear) end crank levers 
for the attachment of the aileron cables. On the machine 
in question, no guns were mounted, but from the various 
fittings it appeared that there were at one time two ma- 
chine-guns mounted above the engine, and with the usual 
interrupting gear for clearing the propeller blades. 

The large engine a 230 h.p. Benz is mounted on 
two longitudinal bearers, which are in turn supported 
from the fuselage by three direct supports at the rear 
a sloping panel of ply-wood, in the middle by tubes slop- 
ing up from the junction of the rear panel to the lower 
longerons, and at the front by another panel of ply-wood, 
this a vertical one. In addition to these direct supports, 
the engine mounting is further braced by tubes to the 
upper longerons, and by diagonal tubes from top to bot- 
tom longerons. It has already been mentioned that the 
main gasoline tank is placed on the floor of the pilot's 
cockpit, while the gasoline service tank is mounted in an 
opening in the top plane. The oil tank, which is com- 
paratively small, is carried under the engine housing on 
the right-hand side of the crank chamber. The propeller, 
which was not in place on the machine, probably had a 



"spinner," or hemispherical MOS, piece over the boss, as 
tins would appear to go well with the nose of the fuse- 
lage, which is of rounded section at tins point. 

The main planes are, as already indicated, tapered from 
root to tip to a very marked extent, the trailing edge 
sloping considerably more than the leading edge. Suc- 
cessi\c ribs are of different depth, as well as chord, owing 
to the fact that the spars, in addition to their convergence, 
are of varying depth from root to tip. Whether, how- 
ever, the ribs change progressively in such a manner that 
all are of actually the same sect inn, but reduced geomet- 
rically, or whether they alter in shape as well as in sise 
has not yet been ascertained, but judging from the way 
in which the spars taper it would appear that the end ribs 
are not of quite the same section as the inner onei. 

( onstructionally, the ribs are of the usual I section, 
with webs which appear to be made of poplar, and with 
flanges of ash. In between the spars the webs are light- 
ened by cutting out in the usual way. The leading edge 
is of pine of U, or, more correctly speaking, of a rounded 
V section between ribs, but left solid where the ribs are 
attached to it. The trailing edge is a thin lath about 1 
in. wide by about 3/16 in. thick. 

The main wing spars are of an interesting construction, 
and their section is shown in the accompanying sketches. 
The two flanges are glued to thin webs (about 5 mm.), 
the whole being wrapped in fabric. No tacks or screws 
are employed for securing the webs to the flanges, the 
glueing and wrapping being apparently relied upon to be 
sufficient for the purpose. At the points where occur the 
ribs a three-ply distance piece is glued into the hollow 
spar, but so narrow is this that in several places it was 
noticed that the tacks through the rib flanges had pene- 
trated the spar flange, missed the three-ply distance piece, 
and had its end projecting inside the hollow of the spar. 
The rear spar, which was of slightly smaller dimensions 
than the front spar, was different in that its upper flange 
had been spindled out, otherwise the two spars were 
similar, also in that in both the top flange was not quite 
so thin as the bottom flange. The spars were constructed 
of what appeared to be some kind of pine, possibly Unit 

Z 'K- 

Where the bolt, serving as an anchorage for the wire 
running to the top plane occurred, the spar was strength- 
ened by a packing piece of peculiar form. This is shown 
in some of our sketches, which will, we hope, help to ex- 
plain it. It will be seen that the saw cuts in the ends 
of this distance piece, leaves four tapering ends, which 
would have the effect of cantilever beams proportioned 
to carry an end load, the latter being considered as the 
lateral load on the spar at this point. Whether this. 
however, was in the designer's mind is doubtful. It is 
more probable that the shape of the piece is the result 
of an attempt at stiffening the spar for a considerable 
distance on each side of the joint, without carrying too 
much weight. The vertical bolt, to which reference was 
made above, is not passed through the spar itself, but 
through an additional stiffening piece glued to the front 
face of the spar. Two horizontal bolts through the spar, 
securing on the rear face of the spar the compression strut 
for the internal wing bracing, are the only attachment, 
apart from the glue, of this vertical packing piece to the 



168 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



spar proper. It is to be imagined that a pull on the inter- 
plane wire must result in a tendency to twist the spar, 
placed, as it is, so far from the vertical neutral axis of the 
spar. Altogether this joint impresses one as being very 
poorly designed indeed, in fact, it lias the appearance of 
not being designed at all. 

The outer inter-plane struts are stream-line steel tubes, 
with a diagonal tube welded to them in the manner shown 
in the illustrations. In addition to this diagonal tube 
there is a wire running diagonally in the opposite direc- 
tion, probably to ensure that the welded joints of the 
struts shall not have to work in tension under the changes 
in load, caused by the travel of the centre of pressure. 

The ailerons, which have their tips at a slightly smaller 
angle of incidence than that of the inner ends, are hinged 
to a false spar slightly to the rear of the rear main spar. 
The section of this false spar is shown in one of our 
sketches. The leading edge of the aileron is in the form 
of a steel tube, partly enclosing which and at some 
distance from it is a strip of three-ply wood, the ob- 
ject of which evidently is to provide the requisite depth 
of the leading edge of the aileron without going to the 
extra weight of a tube of sufficient diameter. The method 
of attaching the ribs to this tube is also indicated in the 
sketches. A short strip of thin steel is bent around the 
tube, its two ends projecting back, and being accommo- 
dated in a slot in the rib. This strip is then soldered 
(and probably pinned, although this could not be ascer- 
tained) to the tubular leading edge. 

Half-way between consecutive ribs, in order to help it 
retain its shape, small distance pieces are tacked to the 
three-ply, having their free ends abutting on the surface 
of the tube. Another sketch shows the tube to which the 
inter-aileron strut is attached. The crank lever of the 
upper-aileron is a somewhat weird and complicated affair, 
having a forward projection curving up over the false 
spar, and dipping down in an opening between two ribs. 
To this projection is attached one of the aileron control 
cables, which runs over a pulley in the lower spar and 
internally in the lower wing to the cranks on the longi- 



tudinal rocking shaft. In plan view the aileron crank 
lever is bent and runs through a rib, the clip attaching 
it to the inter-aileron strut being similar to that of the 
lower aileron shown in the sketch. From this aileron 
crank, a cable passes over another pulley in the same 
casing as that of the first, and hence through the lower 
plane to the controls. It will thus be seen that both ele- 
vating and depressing the aileron is a positive movement. 

The tubular leading edge of the ailerons is supported 
by a small bearing at the inner end, and by two clips of 
steel bent over the tube and bolted to the false spar at 
certain intervals. Thus each aileron is carried in three 
bearings. The outer end of the leading edge of the 
aileron is free. A fact which at once impresses itself on 
one in looking at the lateral control of the Ago is that 
the point from which the aileron is actuated is very near 
its inner end, leaving a very large amount of the aileron 
area outside, a fact which must give rise to considerable 
twisting stresses. 

The tail planes are of similar construction as that of 
the main planes, the same form of box spars being em- 
ployed. The stabilizing plane is brought to the same 
level as the top of the fuselage, by dropping the lower 
longerons, somewhat after the fashion of the old Deper- 
dussin monoplanes. A clip secures the front spar of 
the tail plane to the longerons, while the rear spar is 
attached by means of a sliding clip arrangement, which 
allows (not during flight) of adjusting the angle of inci- 
dence of the tail. The vertical fin, which is of tubular 
construction, is mounted on and moves with the tail plane. 
\o very great amount of adjustment is therefore pos- 
sible, as a comparatively small movement of the rear spar 
of the tail plane brings the rudder against the edge of 
the cut out portion of the fin. (See illustration.) The 
rudder, which is also built of steel tubes, has no support 
above the stern of the body, this being difficult to obtain 
in conjunction with the adjustable fin. The result is 
that the rudder is very much overhung and does not look 
any too strong for its work. 







THE AGO BIPLANE 

1. The gunner's seat. 2. The rear cabane. 3. A cable attachment extensively employed. The cup-shaped socket is machined 
out of the solid and has a slot through which passes the shank of the turnbuckle. Three-ply packing is placed between the plate of 
the fitting and the base so as to make up the thickness of the socket. 4. The gasoline service tank lying on its end on the floor. 
When in place on the machine it is carried in the opening in the upper wing, to the left of the cabane. 






SINC.I.K MOTUUKl) .\KU01M.A.\KS 



Hi! I 



AREA OF 
TAIL. PLANE. 
FT. 



FIGHTtR 
TYPE CV. 

S.S.O/-P. MRCDfS. 




170 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Three views o ' the Albatros " CV 
Fighter. (Description supplied by tli 
British Air Mhiit-try.) 



The Albatros Type "CV" Fighter 



This Albatros biplane belongs to the " C " class that 
is, a general utility machine used for artillery observa- 
tion, reconnaissance work, photography and fighting. 
The machine . na also used for bombing in a small 
way only as it is equipped with a bomb rack holding 
four bombs. 

Aerodynamically the Albatros to be dealt with in what 
follows is, perhaps, chiefly interesting on account of the 
evident attempt on the part of the designer to provide 
as good a streamline body as is possible having regard to 
such external fitments as machine-guns, etc., which nat- 
urally detract to a certain extent from the efficiency of 
the lines of a body of a modern two-seater, where the 
gunner frequently has to stand up, with the upper por- 
tion of his body projecting above the fuselage covering. 
This effort at streamlining is particularly noticeable in the 
nose of the machine, where the aluminium cowling over the 
engine is carried right across, leaving only the exhaust 
collector exposed. In front of the covering of the body 
proper is a cowl shaped as a truncated cone, which serves 
to enclose the nose and reduction gear of the engine, and 
to carry the lines of the body into those of the " spinner " 
around the boss of the air screw. The sides of the body, 
from a short distance behind this cowl to the tail, are flat, 
as is also the bottom, but the top of the fuselage is covered 
with a curved covering of three-ply. 

At the rear the fuselage terminates in a horizontal 



knife's edge, an easy flow being provided for the air by 
running the top covering of the fuselage into the three-ply 
covering of the fin in a smooth curve. Similarly, the 
fixed tail plane, which is of a symmetrical section and 
very deep, has its top surface practically in continuation 
of the top covering of the body, presenting no great and 
abrupt changes in curvature. The total effect is one of 
extremely smootli and easy flowing curves, and the body 
resistance cannot be very great in proportion to the cross 
sectional area of the body. We have no figures of the 
actual resistance coefficient in the formula R = k AV 2 , 
but are inclined to imagine that the coefficient k has quite 
a low value. 

Constructionally the Albatros shows much that is of 
interest, chiefly in the construction of the body. Funda- 
mentally, the Albatros body construction is that employed 
in building light boats and hydroplanes. There is a light 
framework, consisting of four main rails at the corners 
of the rectangular section body, two auxiliary rails some- 
where about half-way up on the sides, and bulkheads or 
transverse partitions of varying shape and thickness along 
the body at intervals. The whole is then, as in boat build- 
ing, covered with a skin of veneer ply-wood, in this case 
three-ply. Regarded as a compromise, this form of body 
construction would appear to be quite good. Without en- 
tailing the time and expense of the true monocoque body, 
it provides a reasonably good streamline form. As a 



SINCLK MOTOKK1) A KKOl'I.A M-.S 



171 



manufacturing proposition it is probably about equal to 
tin- girder type of fuselage, wliili- it has the advantage 
of not requiring any truing up in tin- erecting process, 
tliis follow ing automatically when making the parts over 
j igs am! foriniTs. One advantage this form of boily does 
appear to possess, although to a somewhat li-sser extent 
than tin- trui- inonocoquc shell splinters and rifle anil 
niaehine -ifun bullets are less likely to damage it seriously 
than is the ease with the girder type. In the latter, should 
a longeron be shot through nearly all the strength of the 
structure is yone. whereas this si mi monocoquc structure 
would retain its strength e\en alter dama^in^; some of the 
longitudinal members. 

Finally, there is the ijiiestion of strength for weight. 
Hesults of a test i;i\e the factor of .safety of the Albatros 
body as about (id. and the resistance to bending .;.."> times 
greater than that of a diagonally wired fuselage of the 
same outside dimensions, and having members of the sire 
usuallv employed in structures of this type. The landing 
resistance nl the Miner type of body appeared to be 
greater than that of a cross wired fuselage of the same 
weight, although no actual figures were given showing 
how much greater. 

When looking into the detail construction of the Alba- 
tros body the first thing that impresses one, apart from 
the absence of internal cross bracing, is the extensive use 
that has been made of veneer in the construction of the 



tratist erse bulkheads or formers, which take the place of 
the struts and cross members of the girder type of Univ. 
In Fig. 1 are shown the different bulkheads of the body, 
with dimensions, etc. The rail half-way up the sides of 
the body is placed parallel with the propeller shaft, thus 
serving as a datum line from which to make measurements 
of distances and angles. 

In order to better form a conception of the Alb.it ros 
construction we have shown, in Fig. 1, half-sections of the 
more important and representative bulkheads. In the 
front portion of the Itody the bulkheads, which here have 
to take the weight of the engine, are about I ' ( in. thick, 
and are made up of a number of laminations of wood, 
which are, of course, so placed in relation to one mother, 
that the grains of adjacent layers run at angles to one 
another. 

Fig. ' sin. MS the nose of the Albatros, and clearly in- 
dicates the method of supporting the engine. The first 
bulkhead, it will be seen, is solid, and in at right angles 
to the propeller shaft. The second bulkhead 2, Fig. 
I is lightened by piercing as shown, and is also vertical, 
while the third engine .support is formed by a solid bulk- 
head 3, Fig. 1 - which slo|>cs back no us to support 
the front chassis struts and front cabane .struts at its 
lower and upper ends respectively. As the front engine 
support is clearly shown in the sketch. Fig. '. it has not 
hi en included in Fig. 1. The bulkhead numbered 1 in 



rtlon. of torn* of tb* mora imponul bulkh. 
of tb* Albttro, nhtin blpUux. 




172 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Fig. 1 is merely a former, and does not help to support 
the engine bearers. These are of I-section spruce, and 
have plywood flanges top and bottom as shown in Fig. 3. 
The upper flange is continued outwards to the middle 
longeron so as to form a shelf or bracket at the sides of the 
engine. 

A construction somewhat different to that of the engine 
supports is employed in the panel between the pilot's and 
gunner's cockpits. This consists (4, Fig. 1) of a spruce 
framework faced each side with 3 mm. three-ply, the 
whole having a thickness of 26 mm. (about 1 in.). Be- 
hind the gunner's cockpit is a light partition built up as 
shown in 5, Fig. 1. Two light spruce struts run diagon- 
ally across from corner to corner of the bod}', crossing in 
the center of the fuselage at which point they are rein- 
forced by three-ply facings and triangular blocks glued 
into the corners. 

Their attachment to the upper and lower body longerons 
is of a similar construction, and will be clear from the 
diagram. On their front faces these diagonal struts are 
provided with a 2 mm. flange to stiffen them against 
buckling. A canvas curtain is secured to the front of this 
partition, having in it pockets for maps, etc. 

From this point back to the front where the tail plane 
and vertical fin are attached the formers of the body are 
in the nature of a very light framework of thin struts, 
a typical one being shown in 6, Fig. 1. The general con- 
struction and some of the dimensions of the various mem- 
bers will be clear from the illustration. 

One of the features in which the present Albatros dif- 
fers from previous types is the construction and attach- 
ment of the tail plane and vertical fin. The latter is cov- 
ered with three-ply, and is made integral with the body, 
out of which it grows, so to speak. The construction is 
shown in 7 and 8, Fig. 1, and in the perspective sketch, 
Fig. 4. The tail skid is supported on one and sprung 
from the other of these two bulkheads, as illustrated in 



Fig. 5 (below), the general and detail construction 
of it being evident from the sketches. The tail plane 
is provided with hollow spars which fit over cantilever 
beams integral with bulkheads 7 and 8, Fig. 1, the details 
of which arrangement will be dealt with later. 

Having dealt with the bulkheads or transverse parti- 
tions of the Albatros fuselage, the longitudinals rails will 
be considered next. These are of a somewhat compli- 
cated nature, varying as they do along their entire length, 
not only as regards being tapered from front to rear, but 
also in the different form of spindling out employed at 
the various points, and in the method of reinforcing with 
other strips of wood, partly in order to increase their 
strength where required and partly to make their overall 
section conform to the various angles and curvatures of 
the outside three-ply covering of the fuselage. 

From Fig. 6 a fairly good idea may be formed of the 
shape and dimensions of the longerons at various points. 
The lower one (left hand) is originally of rectangular 
section, but is lightened from point to point by various 
forms of spindling and stop-chamfering. Thus at the 
point B (see key, diagram Fig. 6), the inner face of the 
bottom longeron is spindled out on its inner face with a 
curved cutter. At other points of this longeron farther 
towards the stern various sections are met with, as chan- 
nel, solid rectangle, and L sections of various proportions. 
Between the horizontal stern post and the point at which 
the middle longeron meets the lower one, the latter is re- 
inforced with a triangular section strip, so as to carrv the 
three-ply covering into the sloping side. Similarly at the 
section A, Fig. 6, the longeron, which is here of solid 
rectangular section, is reinforced on the outer side with 
a curved trip, spindled out externally, and with a smaller 
strip on the lower face of the longeron. 

The upper longeron, which is originally of rectangular 
section, is spindled out to channel and L sections at va- 
rious points, as shown in X, Y, Z, Fig. 6. So as to form 



Fig. 5 The tail 
skid and its at- 
tachment on the 
Albatros biplane. 




SINCil.K MOIOHK1) AKUOI'I \\| - 



Fig. 2. Sketch 
showing engine 
bearers of the 
Albatros biplane. 



Fig. 3 Section of 

the engine bearer* 

of the Albatros 

biplane. 



Fig. 4 Con- 
struction of toe 
vertical fin 




174 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



fiitir 




g" (F g General arrangement of the Albatros body. Side elevation and plan to scale. 



an attachment for the curved top of the body, the top 
longerons have glued to their upper face additional strips 
of triangular section while at the point Y, Fig. 6, the sec- 
tion is left rectangular so as to form a support for the 
gun ring. In addition to their function as strengthening 
members these strips serve the further purpose of pre- 
venting the bulkheads from sliding along the longerons, 
as they are cut off where a bulkhead occurs, against the 
front and rear sides of which they abut. In some places, 
as for instance in the front of the body where the cover- 
ing is in the form of an aluminium cowl over the engine, 
the strips are omitted and the cowl attached to turn-but- 
tons as shown in the sketch Fig. 1. At such points the 
bulkheads are prevented from sliding along the longerons 



by a long wood screw passing horizontally through the 
longeron into the bulkhead. 

The middle longerons, which, as already pointed oul 
in a previous article, are horizontal, i. e., parallel to the 
propeller shaft, are of smaller overall dimensions than are 
the four main longerons. They are rectangular section 
lightened in places by stop-chamfering, as shown in a and 
b, Fig. 6. 

Fig. 8 shows, in side elevation and plan, the genera 
arrangement of the fuselage, and should, in conjunctioi 
with the various sections and key diagrams, explain fairlj 
clearly the general layout of the body. Where the tai 
begins two extra longerons on each side have been buill 
into the bulkheads of the body. These two short longer 



FiJ. 9. Sketches of the tall plane and its 
attachments oh the Albatros biplane. 




SIN(;i.K MOTOKK1) A Kl >1M A \ I - 



17.-. 



ons have, in |)l.-in. a direction parallel tn tin- lint- of Hight, 
while tin in.-iin longerons continue cm their converging 
course. Tliis arrangement is indicated in tin- plan view 
K. In side elevation tin- short longerons, against 
which lie the inner ril>s of tin- tail plane, have the same 
ciir\ature a- the tail plane. In this manner the lines 
of the rear part of the body are not spoiled, while an easy 
flowing eur\e is prox ided for running the tail plane into 
the bodv . 

Keferenee lias already been made to the peculiar attach- 
ment of the tail planes to the body. The sketch at the 
top of l-ig. !' shows in perspective this attachment, which 
is also illustrated in the diagram in the Imttoni left-hand 
corner of Fig. >. The bulkheads of tin body are extended 
outwards tn form cantilever heanis which support the tail 
plane. There are three of these cantilever beams, while 
further support is provided for the tail plane leading and 
trailing edges as indicated in the sketches. The .spars of 
the tail plain- are of the box tvpe. built up of ash flanges 
with thin three-ply sides, eut out for lightness. These 
spars an s,i proportioned that they rit over the cantilever 
beams, which do not. it will be seen, run right out to 
the edge of the tail plane, but are finished off just outside 
the second tail plane rib. No external braeing of the tail 
pi me is provided, the depth of it and the method of mount- 
ing being relied on for the necessary strength. 

To pro\ idc against the tail plane sliding off its canti- 
lever supports it is secured at the leading and trailing 
due. The former attachment is indicated in the bottom 
right-hand corner of Fig. 9. A sheet steel shoe fits over 
tin corner of the leading edge and inner rib, and through 
this shoe a long bolt passes, which runs across the body to 
a similar shoe on the other side. In Fig. 10 is shown the 
rear attachment of the tail plane. A sheet steel box sur- 
rounds the corner of the fuselage. Welded to this box is 



a short tnlx- which tits into n circular recesi in the end of 
the tr.iiling edge of the tail plain-. As tin- elevator tulx- 
runs right across and is fitted with collars Ix-aring against 
the sides of the clips that form the Itcaring for the elevator 
tube, the trailing . -dgc of the tail plane is prevented from 
slipping outwards. 

The manner employed of forming bearings for the > I. 
vator is indicated in the diagrams of Fig. 1O. A steel strip 
is Ix-nt over the tube, and its two free ends are Ix-nt over 
and tit into slots in the trailing edge of the tail plane. 
Each clip is tin n secured to the tail plane by a vertical 
bolt as shown in the diagram. The trailing edge of tin- 
tail plane is spindled out to a si-mi circular section as 
shown, and a curved metal distance piece is screwed to 
this trailing edge or spar, so an to form tin second half 
of the bearing of which the bent steel strip forms the 
other half. To remove the elevator the bolts securing the 
clips are undone; the clips are then bent outwards until 
their free ends clear the slots, when the elevator can be 
removed bodily. 

As the elevator i.s built of steel tubing throughout, wood 
I'hi. ks of the shape shown in detail I, Fig. 10, are em- 
ployed for attaching the fabric covering. These blocks 
span over the steel strip bearings, and are secured to the 
tubular leading edge of the elevator by screws as shown 
in section Ml!. A hole in the opposite wall of the tube 
serves for the insertion of the screwdriver. 

As regards the remaining details of the tail of the Alba 
tros little need be said, as they are fairly evident from the 
plan and sections of Fig. 11. It will suffice to point out 
a rather ingenious construction of the leading edge of the 
tail plane. In plan the tail plane, it will be seen, is 
roughly semi-circular, and its leading edge therefore has 
to be shaped to this curvature. As an ordinary strip of 
.solid spruce spindled out to a semi-circular section would 



Flft. 10. DcUiK of the tail plane and 
elevator attachment on -the Albatro* 



STEL CLIP 
\ x-~-'Lx 




JeerntM A .A 



DETAIL/. 



176 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



ALBATROS 
TAIL PLANE 




Fig. 11. General arrangement and dimensions of the members of the tail plane on the Alb*tro biplane. 



scarcely be strong enough for this work, a different method 
has been employed. It appears that originally the lead- 
ing edge of the tail is made up of four laminations of ash, 
having, of course, their grains running in slightly different 
directions. The rectangular section spar thus formed is 
then spindled out to a semi-circular section, as shown in 
the diagram, leaving the impression that the leading edge 
is made up of seven thin strips of wood glued together. 
The resulting leading edge appears to be one of great 
strength, while at the same time being quite light. 

The cockpits of the Albatros are arranged in the fash- 
ion now universally adopted for two sealers, by Allies as 
well as by the enemy, i. e., the pilot in front and the gun- 
ner in the rear cockpit. The pilot's seat is mounted, in 
the Albatros, on the main fuel tank, which has two an- 
nexes on top, one on each side of the seat. This arrange- 
ment is clearly indicated in Fig. 12, in which the small 
clips preventing the seat from sliding about on the tank 
will be noticed. The filled cap is mounted on a tubular 
projection extending through the fuselage covering, thus 
enabling the tank to be refilled from the outside. A 
smaller auxiliary tank is mounted above and to the rear 
of the main tank, in the gunner's cockpit, as a matter of 
fact. Botli tanks are connected up to a by-pass or dis- 
tributor, so that both or either tank can be connected up 
to the engine, two pumps being provided for maintaining 
the necessary pressure, one driven by the engine and the 
other hand operated. Thus, whatever tank is being used, 
petrol is fed to the carburetor under pressure. This has 
probably been a necessary provision, as the tanks are 
placed relatively low and gravity feed would, therefore, 
be apt to be unreliable when the machine is climbing at a 
fairly steep angle. 

Constructionally the petrol tanks are of interest in that 
they have been internally braced by rods running across 
from side to side, the attachment of the rods being visible 




Eiifi 



on the outside of the tank as shown in Fig. 12. To pre- 
vent the petrol from slushing about inside when the tank 
is nearly empty baffle plates are fitted dividing the main 
tank longitudinally into five compartments, communicating 
with each other through the circular openings shown in 
the section of the tank, Fig. 12. As the supply pipe 
leaves the tank fairly high up it can be seen on the 
front right-hand side of the tank in Fig. 12 it is carried 
down inside to the bottom of the tank so as to enable the 
last drop of petrol to be forced out and into the carbu- 
retor. The main tank is mounted on brackets as shown 
in one of the sketches, and is secured by metal straps hav- 
ing an arrangement for adjustment. 

In Fig. 13 is shown the general arrangement of the 
controls. There is a transverse rocking shaft at each 
end of which are mounted crank levers for operating the 
elevators, while in the centre, pivoted so as to be free to 
rock laterally, is mounted the main control lever. 
Mounted on the transverse shaft, but not moving with it, 
is another lever, which operates the claw brake mounted 
on the wheel axle. The arrangement of this brake is 
shown in Fig. 14. By pulling the lever the free end of 
the claw brake is pulled upwards, thus causing the claw 
to dig into the ground. On releasing the lever, the brake 
is returned to its normal position by the action of the 
spring shown in the sketch. 

The transverse rocking shaft is carried, as indicated in 
Fig. 14, in two bearings mounted on the lower longerons. 
A forward and backward movement of the control lever 
causes the shaft to oscillate, and with it the two crank 
levers to which are attached the elevator control cable. 



SI\(;i,K MOTOKKI) AKUOl'l. \\ l.s 



177 



Tin -sr cables run from (lit- crunk lever, around a pulley 
slightly forward of the transverse -.halt a-, shown in the 
sketch, anil hence to tin- top crank ICMT on tile elevator. 
Tin- return calilc runs from the crank on tin under side 
nt tile elevator to tile crank on the transverse shaft. Kn 
route these cables pass over pulleys Iiloiilited in the rear 
position of the fuselage, these pulleys hcina shown ill 
detail in sunn of the accompany ing sketches (Fig. 15). 

As regards literal control, the general arrangement of 
this is indicated in diagrammatic- form in Fig. 16. From 
the control lever the direct cahlc passes over a pulley on 
the transM-rse shaft, along through the lx)ttom wing, 
around another pulley in the wing, and hence to the rear 
half of the aileron crank le\er. The return ealile runs 
from the front half of the aileron crank lever, around 
.mother pulley in the lower wing, through the wing and 
through the transverse shaft to a pulley on the other side 
of tin' control lever, and hence to the screw on the con- 
trol lever. The details will he clear from Fig. 13. 

The foot l>ar operating the rudder is mounted on a pyra- 
mid of steel tulies, and the rudder cables arc taken, not, 
it will In seen, from the foot bar itself as is generally 
done, hut from a short lever projecting forward at right 
angles to (he foot har. From this lever the cables pass 
over pulleys and to the cranks on the rudder. It will be 
seen that provision has been made for making adjustments 
of the loot bar to suit pilots of different height by fitting 
on extra foot bar. 

As in the majority of German machines, provision has 
1'ei n made for locking the control lever in any position 



either Hying level, climbing, or descending. This is ac- 
complished ly means of a collar free to slide along tin 
control column, but U m- split and provided with a bolt 
for tightening up. when the collar is locked in position 
on the control column. Anchored to this collar by two 
screws is a fork end. from which a tnU runs dou n and 
forward to terminate in a ball rind socket joint secured to 
the bottom of the fuselage. This ball and socket joint, 
it will In- set n. enables the control column to be moved 
freely in any direction, and to allow it to I*- moved 
from side to side, even when the forward movement of 
the column is prevented by locking the collar. In this 
manner, the pilot can lock the elevator, while operating 
the control column from side to side for lateral control 
with his knees. 

While on the subject of controls, reference might IM- 
made to the crank levers on the elevator and rudder. 
These are shown in Fig. 17, from which their construc- 
tion will be evident. The crank lever of the elevator has 
projecting from it a tapering tube running to the trailing 
edge of the elevator. The tubular rudder post is working 
in bearings similar to those described in our last issue 
when dealing with the hinges for the elevator. At the 
bottom the rudder tube fits into and is supported by a 
socket carried on a clip bolted to one of the transverse 
bulkheads of the fuselage. A peculiarity characteristic 
of the Albatros is the method of attaching the control ca- 
bles to the crank levers. A socket is formed in the end 
of the crank lever, and into this fits a cup- shaped piece 
of steel machined on one of the bolts of the wire strain, r*. 




Fig. 14 Dlaftrmmatic 

ktcb of the claw brk 
on tb AJbtro. 




Ki(r. l:t. Tin- controls of I In- Ailmtros liiplnnr. Inset* show the hnll anil socket joint 
for thr control l.-v.-r locking arrangement, and hand grip with pin trigger on the main 
control lever. 





Fig. 16. Diagram of the aileron control system of the Albatros Fighter 




Fig. 15. " A " shows the pulley over 
which the elevator cable passes after 
leaving crank lever on rocking shaft (See 
Fig. 13). "B" The pulley mounted on 
the top longeron (in front of the tail 
plane) over which the elevator control 
passes. "C" This pulley bolted to the 
middle longeron just ahead of the tail 
plane guides the elevator cable. " D " 
This pulley guides the rudder cable in 
front of the footbar. 



Fig. 18. The machine-gun and its 
mounting on the Albatros Fighter. The 
bag for the spent cartridges should be 
noted. When not in use, the butt of the 
gun rests in the clip shown. The two 
smaller sketches show the locking devices 
for the gun pivot (left) and the gun 
ring (right) 



Fig. 19. So as to be out of the way 
when the gunner is firing from a stand- 
ing position, the seat on the Albatros 
Fighter is hinged and sprung as shown 
in this sketch 




Fig. 17. Elevator and rudder crank levers on the Albatros biplane. (A) Elevator crank lever with its ball socket joint for the 
turnbuckle. (K) Bottom rudder bracket and crank lever. (C,"\ Mounting nf HIP rmlHcr 



SIM.l.l. MOTOKKD AI.KOl'L. \.\KS 



IT'.t 







t-'if. ii. Shrrt strrl s|uir IHIX and 
socket fur compression tulw i>f the up- 
|MT pl.im- of tin- Mli.-itrus liipl.mi- I In- 
Uittniii skrtch shows the ;itt.-i. liim-nt of 
the terminals for the Interplane cnMcs 
ami struts 



= ctlons ..I Hi leading edge, in 'in spurs nnd false spar of the AHwtros 

liiplime 



nuu-li in tin- same manner .-IN the terminal attachment of 
tin main lift cables. Thus any vibration in the <oiitr.il 
cable is not transmitted to the crank lever, the cup-sha|>cd 

f tin- turn-buckle bolt being free to move in it* 
sin k. t in tin- crank lever. 

n nee has already been made to one part of the 
armament of the Alliatros. namely, the s\ nchroni/.ed ma- 
chin, -mi op. rated by the pilot from the trigger on the 
main control column. In addition there is a movable ma 
elnni i;un mounted on the usual gun ring in the rear cock- 
pit. Tin- a< n. ral arrangement of this gun mounting is 
slion in (I,, sketch. Fig. 18. The gun ring itself is built 
up f thin three-ply wood, and runs on small rollers on 
its support so as to reduce friction. It is prevented from 



tilting up by wooden angle pieces screwed to its undcr- 
siil.- and overlapping the fixed support. 

The machine-gun is supported on the gun ring l>\ -i 
swivelling fork, which can be raised and lowered as re- 
quired, and which can be locked in any desired position 
by the locking arrangement indicated in the sketch of 
the general arrangement. In addition to its circular mm. 
ment integrally with the gun ring, the machine-gun may 
be swung laterally on its pivot in the gun ring. Her.- 
also a locking device is provided in the shape of a split 
collar locked by an I. bolt, as shown in one of the insets. 
The other inset in Fig. 18 shows the lever by means of 
which the gun ring is locked in any desired position. 

As presumably it frequently happens that the gunner 




t. Corl mntftmtat of the .pp.r fcrft-bwxl wing at ln AIbtro. blpte*. to 



180 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



wishes to fire from a standing position his seat has been 
so arranged as to swing into a vertical position as soon 
as it is relieved of its weight. This is accomplished by 
means of a spring under the seat, as shown in Fig. 19, 
which is, we think, self-explanatory. A strip of wood 
runs transversely under the seat and projects a short dis- 
tance on either side. These projections rest, when the 
seat is in a horizontal position, in brackets secured to the 
sides of the fuselage. 

The Albatros biplane belongs to the C class, that is 
to say, is a general utility machine variously used for 
fighting, reconnaissance, artillery spotting and photog- 
raphy, and is therefore not to be considered a bombing 
machine. It is, however, provided with racks for a small 
number of bombs four, to be exact - presumably by 
way of cases of emergency when a suitable target might 
present itself. Fig. 20 is a diagrammatic perspective view 
of the bomb racks and bomb release gear. The bombs are 
secured underneath the main tank in the pilot's cockpit, 
but they are released by the gunner in the rear cockpit by 
means of a small lever and quadrant shown in Fig. 20. 

The bomb racks are in the form of sheet steel sup- 
ports, against the bottom of which rest the nose and the 
tail of the bombs respectively. These brackets are se- 
cured to transverse members in the bottom of the fuselage, 
which have been omitted in the drawing for the sake of 
clearness. The bombs themselves are supported by a 
steel strap or band, passing underneath and approximately 
under the middle of the bombs. At one end the straps 
are hinged, while at the other they are provided with an 
eye, which is secured in the hook under the release trigger. 
One of the sketches in Fig. 20 shows in more detail the 
hook in which the eye of the strap rests, and the trigger 
by means of which the strap is released. The trigger is 
pivoted near its centre, and has an upward projection to 
which is attached a small coil spring resting in a groove 
in the base supporting the hook. When the cam on the 
transverse shaft presses down the rear end of the trigger, 
the front end moves upward against the tension of the coil 
spring mentioned above, thus releasing the strap and with 
it the bomb. 

As regards the cams which operate the bombs, these are 
mounted on a transverse shaft running across the bottom 
of the fuselage. There are four cams, each operating its 
trigger, but the gearing of the camshaft is such that it 
requires five pulls on the lever in the gunner's cockpit 
to rotate the shaft through a complete revolution. One 
of these pulls of the lever has no corresponding cam on 
the shaft, and has, it appears, been incorporated in order 
to provide an equivalent of a safety catch. When all the 
bombs are in place the first pull on the lever does not 
release a bomb, but merely brings the cam for bomb No. 
1 into position, ready to press, on the next pull of the 
lever, the trigger for the first bomb. This has evidently 
been done as a precaution against accidentally releasing 
a bomb until the machine is approaching an objective. 

We now come to consider the method of operating the 
transverse camshaft. Near the right-hand side of the 
fuselage there is mounted on the camshaft a small ratchet 
having five teeth, as shown in Fig. 20. On this ratchet is 



a small cam, roughly of cone shape. This cam engages 
with grooves in the pulley around which passes the operat- 
ing cable. A small leaf spring engages at the proper mo- 
ment with the notches in the ratchet and prevents the 
shaft from rotating in the reverse direction. One end 
of the operating cable is attached to a coil spring secured 
to the side of the fuselage, and passes from there around 
the pulley to the lever in the gunner's cockpit. Assuming 
that the first cam is in position ready to release its bomb, 
a backward pull of the lever rotates the pulley and with it 
the ratchet and camshaft, thus pressing down the trigger 
of one of the bomb racks and releasing a bomb. When 
the gunner releases the lever this is pulled forward to its 
normal position by the spring on the side of the fuselage. 
The little leaf spring engaging with the ratchet prevents 
this and the shaft from following the pulley round in the 
opposite direction, and the cam on the ratchet sliding up 
the sloping bottom of one of the five grooves in the face 
of the pulley forces the pulley away from the ratchet 
against the compression of a small coil spring shown in 
the sketch. By the time the lever has reached its for- 
ward position, the pulley has revolved to sucli an extent 
as to bring the cam on the ratchet into the next groove in 
the pulley, and when the lever is again pulled the whole 
action is repeated. The sketch will probably help to make 
the action clear. 

In addition to a bomb release lever, there is in the gun- 
ner's cockpit another lever, the function of which appears 
to have been to engage and disengage a clutch near the 
engine, by means of which a drum is operated carrying 
the aerial of the wireless. In the bottom of the gunner's 
cockpit, near the left-hand side, is an octagonal opening 
in the floor, in which, so far as we can make out, the 
camera was mounted. The compass, so as to be visible 
from both cockpits, has apparently been mounted in a 
circular opening in the right-hand lower main plane. 

We now come to deal with the wings of the Albatros. 
These are, generally speaking, of the construction favored 
by the Albatros designer, that is to say, the front spar is 
well forward close to the leading edge, and the rear spar 
is approximately half-way along the chord. In addition, 
there is a third false spar, which is not, however, con- 
nected up to the body nor supported by any struts, and 
which cannot therefore be considered as taking any par- . 
ticularly important part of the load. It 'will, therefore, 
be realized that the rear main spar may at small angles 
of incidence, when the centre of pressure moves back-J 
wards, be called upon to support all or nearly all of the 
load. This has evidently been guarded against in the 
Albatros by making the rear spar of generous proportions. 
Both main spars are made of spruce, and are of the box 
type, consisting of two halves spindled out and glued 
together with a hardwood tongue running through both 
flanges. The ribs are of I-section, with spruce webs and 
ash flanges. Between the main spars false ribs are em-] 
ployed half-way between the adjoining main ribs, so as] 
to better preserve the curvature of the wing for this dis- 
tance. 

The general arrangement of the upper left-hand wing 
is shown with dimensions in F'ig. 21, from which the gen-j 



SI\(;i,K MOTOKKl) AKKOl'L. \.\I.S 



Ihi 



i ral lay-out of tin- wing will he clear. Tin- intrrn;il drift 
wiring is in the form nl the Lays, tin- i-iiiii|irrssiiiii struts 
fur this wiring being in tin form of circular section steel 
tulii-s. Iii the two nun r l>.i\s both drill :uid anti-drift 
wins arc in duplicate and arc approximately 1 l i S.\\'.(i. 
Tin nc\t two hays !ia\e single wiring. ,-ilso of 1 v! S.\\'.(i., 
while the outer Itay has single wiring of I 1- S.W.G. 

The attachment for the compression tulies and tin- drift 
and anti-drift wires is shown in Fig. 22. A box of thin 
sheet steel surrounds the spar at this point and is bent 
o\er and liolted as shown in the small section in Fig. 22. 
On the inner face of the spar this sheet steel box has two 
wiring plates stamped out. which receive the drift and anti- 
dritt wires. A short cylindrical distance piece is welded 
on to tin lio\. and around this tits a short tubular sleeve 
held in position by a slit pin. This sleeve forms a soekct 
for the tubular compression strut. 

Vertically the spar is pierced at this point by three 
holes, for the holts securing the interplane strut and the 
two interplane cables. The attachment for the latter is 
shown in Fig. _>,'. The base plate has machined in it two 
recessed circular openings which receive the two terminals 
for the cables. These terminals are prevented from ro- 
tating by a small rivet as shown in the sectional view. In 
order to further strengthen the spar at the point win-n- 
it is pierced by these three bolts, the spar ia left solid for 
a short distance on each side of the box, and packing 
pieces an- interposed between the box and the spar, so as 
to bring it up to an approximately rectangular section in 
order to get the bolts coming through the spar and base 
plate at right angles. 

In 1'ig. .':> are shown sections, to scale, of the two main 
spars, the false spar, and the leading edge. The trailing 
edge is. as in the majority of German machines, in the 
form of a wire. 

Fig. ' t shows the shape and dimensions of the wing 
section. As in nearly all German machines, the camber 
is. it will ! seen, extremely great, both as regards the 
upper and lower surface. 

The precise object of employing such a wing section 
is not at once apparent, but it should be remembered that 
the German machines carry a comparatively great load 
per square foot of wing surface, and the probabilities are 
that the section has been designed with a view to enable 
the wing to support this high load at comparatively great 
altitudes, and has, therefore, probably an excess resist- 
ance at lower levels. 

In addition to the general construction drawings of the 
Albatros wings, shown in a previous illustration, we are 
able to gi\e some of the more interesting constructional de- 
tails. Fig. 26 shows some details of the upper left-hand 
wing near the tip, and also the general arrangement of one 
of the ailerons. As will be gathered from the sketch at the 
left top of Fig. '<>. the wing flaps are built up of steel 



tubing throughout, and each aileron is balanced by a for- 
ward projection, not. as in the dothas. outside the tip of 
the main wing, but working in an opening ill the main 
plan.-. As in ne.irly all German machines, the aileron is 
not hinged to the rear main spar, but to a third false spar 
situated between the rear main spar and the trailing edge. 
The method of hinging the aileron will U- clear from the 
detail section and elevation at A. A. st.cl clip is bent o\cr 
the tube of the aileron and has its forward ends bent into 
grooves in wood blocks on the front face of the spar, 
much in the same manner as was employed in the ease of 
the elevator hinge ami di-scriln-d when dealing with that 
member. As in the case of the elevator hinge the fabric 
covering of the wing flaps is attached to wood blocks 
screwed to the tube. 

The crank lever for operating the wing flap is in tin- 
form of an elliptical section tube tapering towards its ends. 
I'.ach half of this crank lever carries three wiring clips, 
as shown at li. It will be seen that by providing three 
clips on each end instead of one. a means for varying tin- 
gearing of the wing flap control is furnished. If a pilot 
wishes the machine to be fairly sensitive on the lateral 
control he will naturally attach his wing flap cables to tin- 
inner clips, since thereby a movement of the control lever 
will result in a larger movement of the wing flap. On 
the other hand, if be prefers to have a large movement 
on his control lever without too great corresponding angu- 
larity of his wing Haps or ailerons. In- will attach his cables 
to the outer clips, as this will result in a " gearing down " 
of the wing flap. 

The forward end of the wing flap crank lever works in 
a slot between two closely spaced ribs, as shown in the 
sketches. At this point the ribs are strengthened by mak- 
ing them of the box type for their rear portion, and the 
ash flanges of the ribs arc left wider over this portion, 
while being reduced to their normal width from the rear 
spar forwards, as indicated in the sketch. At this point 
also occurs the strut and lift cable attachment. This 
strut being the last, there is only one cable instead of the 
two occurring where the inner struts are attached, other- 
wise the attachment is similar in principle to the usual 
(ierman practice. The spar box and strut and cable at- 
tachment is indicated in the detail sketch at C'. The tubu- 
lar compression strut is secured in the same manner as 
that of the fitting previously referred to. 

As previously pointed out, the trailing edge of the Alba- 
tros wings in in the form of a wire, and the method whereby 
the outer main rib is prevented from bending sideways is 
illustrated in the detail sketches at I) and I In addi- 
tion to the wire forming the trailing edge, there in another 
wire running parallel to it and carried right through the 
wings, the object of which appears to be to provide a 
counterpoise capacity. The wiring in the Albatros is not 
extensive, and in the case of the fuselage it is absent alto- 



. 2t_Tt wing Mellon of Ibt AllMlrol btplu*. 



182 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Fig. ^5. The spar box and its attachment to the fuselage of the Albatros fighting biplane 



gether, and it therefore appears probable that the thin 
cables running along the wings and the longerons of the 
fuselage serve the purpose of providing the necessary 
amount of wiring, otherwise one is at a loss to account 
for their function. 

It has always been customary for German aeroplane 
designers to provide some easy means for quickly detach- 
ing the wings from the body, and the present Albatros is 
no exception from the rule in this respect. The cables 
themselves are not, it is true, fitted with the quick release 
devices one finds on the L.V.G., for instance, but the spar 
attachment has been designed to facilitate the removal of 
the wing, even if that of the cables has not. In Fig. 25 is 
shown the spar box and its attachment of the lower wing. 
A sheet steel box surrounds the root of the spar, and has 
in its end a slot into which fits the lug secured to the 
side of the body. 

Welded to the side of the spar box is a socket forming 



a bayonet joint, into which fits a pin fitted with a small 
spiral spring. The spar is held against the side of the 
body with the lug projecting into the spar box, and the 
pin is inserted and given a twist so as to bring the pro- 
jections on the pin into the notches in the bayonet joint, 
and the spar is secured. For removing the wing all that 
has to be done is to press the pin slightly against the 
action of the spiral spring, give it a twist and pull it out 
of its socket, and the spar can be withdrawn. The spar 
is secured to the spar box by screws, and the box is fur- 
ther secured against tensional loads by a steel strip about 
a foot long running along the face of the spar and an- 
chored at its other end by a bolt passing horizontally 
through the spar. 

As the lower wing spars are subject, in addition to 
the bending moment owing to the lateral load on them, 
to tension, the attachment to the body has to be such that 
it will resist a tensional load as well. 




Fig. 26. The wing flap and some wing details of the Albatros fighting biplane 



SINCI.K MOTORED AKU( )IM A \ I - 



IH.M 



The Inn to which the spar is attached tits into a recess 
in the h.ise plate formed by stamping. Tin- i\i-il pull 
is transmitted across tin luittiiin of the t'usi la^c via the 
brackets .-mil strips shown, which .-ire bolted to the base 
plat, holding the lug. In order to prevent tin- lug from 
tiirnini; it is riveted by four rivets as indicated. 

The upper planes are attached, as in nearly all (.er 
man iiiacliiin s. to a four-legged cabane. In addition to 
supporting the win^s the cahane of the Alhatros carries 
the radiator, wliirli is of the same shape as the wing 
siction and winch tits into an opening in the wing. The 
raliane is shown in Fig. -J7. It will he seen that one of 
the cahaiie legs carries for a short distance the water tube 
from tin radiator to the engine. 

The attachment of the upper wing spars to the e d. in. 
is somewhat similar to that of tilt- lower spars, inasmuch 
as a pin fitted with a spiral spring secures the spar to the 
raliane. Here, however, tin- similarity ceases. Instead 
of the spar lio\ into which tits the lug on tin- side of the 
body, the upper spars are provided with n forked lug, 
irohalily a forging machined to shape, of the form shown 
n l'ig. 28. Tin 1 lug of the opposite spar is of the same 
Impc. lint is. of course, reversed, so that when the two 
pars meet against the top of the cahane. their respective 
ar. staggered in relation to one another. From the 
mil attachment of the lugs it will lie seen that as 
hcv ar. staggered on the spar and in relation to one an- 
ithir. the spars will, when in plaee. come in line with 
lie another. On one of the outer faces of the forked 
iiiice is left solid, and is shaped to receive the 
onnded end of the op|(site lug. This has prohably been 
lone in order to reduce the shearing stress on the pin se- 
uriiiir tin- lugs to the cabane. 

The wing-Hap crank-lever of the lateral control is 
lori/ontal. as in so many other German machines. The 
untrol cahlcs for the wing-Haps are. therefore, arranged 
in vv hat unusual way. The details of this arrange- 
ire shown clearly in Fig. .SO. From the front and 
rear half of the wing-flap crank-lever cables pass down 
o pulleys enclosed in a casing mounted on the rear face 
if the hack spar of the lower plane. After passing over 
'iilleys the control cables pass through the rear 
*pr to another pair of pulleys mounted on the tubular 
onipr. ssion strut, and hence to the controls in the body. 
\ light framework surrounds the pulleys as shown in the 
sketch, and forms the support for the hinged inspection 
v means of which the condition of the pulleys and 
rontrol cables may be examined. The tension of the 
P control cables in regulated by means of turn 
- inside the lower wing. These tiirnbnckles are 
situated close to the side of the body, and are rendered 
ihle by hinged aluminium inspection doors on the 




lower surface of the bottom wing. In order to pnv.nt 
the tnrnhiicklcs lr..m .-at.'hing against the . .1^. s of the 
wing rilis. cables and tiirnbnckles arc surround. <l lit a 
tube of aluminium, lining on its under side an o|iciiing 
with edges Hanged outwards to reduce the danger of a 
slack control cabl- allowing the turnhuckh to touch the 
edges of the opening ill the tube. 

\- in the majoritv of modern tractor aeroplanes, the 
undercarriage of the Albatros is of tl p. . and i 

built of sin am line steel tubing throughout. Th< 
eral arrangement of tin- undercarriage i shown in I 
--'!. from which it will be seen thnt only the front pair 
of undercarriage struts are diagonally braced by cable*. 
Reference has alrcadv been made to the claw brake, and 
to the manner in which it is opi rated from the pilot's 
cockpit. In the sketch its general arrangement will In- 
evident. The front and rear struts of the undercarriage 
fit into split sockets at the top and liottom rcs|icctivcly. 
from which they may he withdrawn by undoing the bolts 
of the socket, thus facilitating replacement in case of dam- 
age due to a rough landing. 

Front and rear strut sockets are attached to the body 
in a slightly different manner, as will be seen from the 
sketches of Fig. 29. In the case of the front strut sockets 
these arc welded to a wide steel strip passing underneath 
the bottom of the body, thus tending to distribute the load 
over a greater area of the body. The details arc .shown 
in the general arrangement sketch, and in V. Fig. 'J!. 
.lust inside the strut socket the cup-shaped terminal for 
the diagonal bracing cables of the undercarriage is sc- 
i ured. while a short distance above the socket in situated 
the attachment for one of the main lift cables. This ball 
and socket joint, which is used with slight variations on 
nearly all dermaii machines, appears to be almost tin- 
only tilting that may be truly said to have been standard- 
ized by the Germans. It is made in a range of sizes, no 
doubt all made to some uniform standard, so as to render 
it applicable to a number of different types of machines. 
The details of the fitting are indicated in i and X, Fig. 29. 
The base plate securing the hemispherical socket to the 
body or whichever part of the aeroplane the terminal hap- 
pens to be attached to. is recessed, probably by stamping. 
and into this recess fits the Hange of the socket. The 
socket itself is free to turn in the circular recess of the 
base plate, thus allowing the cable to accommodate itself 
to any angle desired. The end of the turnbuckle has two 
Hats on its shank which prevent the strainer from turn- 
ing. For purposes of adjustment the slot in the socket 
is enlarged at its inner end so as to allow the strainer 
to turn when in a position at right-angles to the base plate. 

The attachment of the rear chassis strut to the Ixidy is 
shown in :>, Fig. 29. The base plate to which the strut 




I'hr c.b.ne supporting the radiator ami upper plane Fig- * -Sketch showing lup on mot f upper main wing .par. 
>f the \llmtros biplane. Note the manner of carrying the water 
hrouph one of the culiane legs 



184 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




socket is welded is of angle section, and is secured, via 
brackets as shown, to steel strips running across the body, 
and which take the tension of the lift cables. This ar- 
rangement is somewhat similar to that of the lower wing 
spar attachment, which we described in a recent issue. 

The lower ends of the two Vees are formed by short 
lengths of bent tube of slightly larger dimensions than 
the struts themselves, for which they form sockets. The 
details will be evident from the sketches and hardly need 



any explanation. Running across the undercarriage par- 
allel with the axle are: in front a compression tube, and 
behind a stranded cable. 

A steel strip protects the rubber shock absorbers from 
contact with the ground, and a padding of leather is in- 
terposed between the axle and the bottom of the Vee. 
The upward travel of the wheel axle is limited by a short 
loop of cable, against which the axle comes to rest after 
travelling the permissible amount. 




Side view of the Albatros C-V Fighter 



The chassis of the Albatros C-V Tvp 



SIN<;I.K MOTOKK1) AKK01M..\M> 



185 



THE FOKKER SINGLE-SEATER 
BIPLANE. Type D.7. 




SPAN 

CIKIkll TOP PLANE 

., BOTTOM .. 
OVERALL LENGTH 
TAIL PLANE SPAN 
MEKiMT ... 
AIRSCREW 

GAP 

STAQQER 
ENOINE 



4- r ,. 
i iir.. 

Mercedes 160 h p. 




186 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Three views of the Fokker Single Seater 

The Fokker Single Seater Biplane Type D-7 



This aeroplane presents features of very great inter- 
est, whether viewed from the standpoint of aerodynamic 
design or of actual construction. The machine which has 
been the subject of investigation was, unfortunately, 
rather extensively damaged, thus making absolute ac- 
curacy of description difficult, and trials of performance 
impossible. 

A similar machine, however, has been tested for per- 
formance by the French authorities, who have issued the 
following report: 



1,000 
2,000 
3,000 
4,000 
5,000 



Altitude 

metres 

(3,281 ft.) 

(6,563 ft.) 

(9,843 ft.) 

(13,124 ft.) 

(16,405 ft.) 



Time of climb 
4 mins. 15 sees. 
8 mins. 18 sees. 
3 mins. 49 sees. 

;2 mins. 48 sees. 

38 mins. 5 sees. 



The principal dimenjfens are as follows: 

Span 

Chord (upper wing ) 

Chord (lower wing) 

Overall length 

Gap 

Area of upper wings (with ailerons) 



Speed at 
this height 

116.6 m.p.h. 
114.1 m.p.h. 

109.7 m.p.h. 
103.5 m.p.h. 

94.9 m.p.h. 

29 ft. 3 1/ 2 ins. 

5 ft. 2 y 2 ins. 

3 ft. Ily 4 ins. 
22 ft. ll>/ 2 ins. 

4 ft. 2 ins. 
. . . 140.7 sq. ft. 



Area of lower wings 78.3 sq. ft. 

Area of aileron (one only) 5.7 sq. ft. 

Area of balance of Aileron 5 sq. ft. 

Area of horizontal tail plane 21.1 sq. ft. 

Area of elevators 15.2 sq. ft. 

Area of balance of elevator l.l sq. ft. 

Area of fin 2.8 sq. ft. 

Area of rudder .5.9 sq. ft. 

Horizontal area of body 35.6 sq. ft. 

Vertical area of body 58.6 sq. ft. 

Area of plane between wheels 12.4 sq. ft. 

The following data regarding weights is taken from a 
French source : 

Weight of fuselage, complete with engine, etc 1. 3 -'.'. 2 Ibs. 

Weight of upper wing with ailerons 167.2 Ibs. 

Weight of lower wing 99.0 His. 

Weight of fin and rudder 6.6 Ibs. 

Weight of fixed tail plane 17.6 Ibs. 

Weight of elevators 9.9 Ibs. 



1,622.5 Ibs. 
Wings 

As in the Fokker triplane, the extreme depth of wing 
section and the absence of external bracing are distinctive 
features. Both upper and lower wings are without di- 
hedral, and are in one piece. 



SINCiLK MOTOKKI) A KHOI'I .A M -s 



Sections of 111!' willL' -p.-ir of tl- l-'l 

1)7 






* 3. 






:. 4. 



Wing Construction 

In sharp contradistinction to the fuselage, which is con- 
st ructcd of stcrl even inclndim; members where wood 
is almost tmi\i rs.-illy used, the wings contain no metnl 
parts, if we exclude strut fittings and other extraneous 
features. There are no steel compression members, hut 
where the internal wiring lugs occur, special box-form 
compression ribs are fixed. The leading edge is of very 
thin three-ply, which has a deeply serrated edge, finish- 
ing on the main spar. The ribs are of three-ply, and are 
not lightened, although holes are, of course, cut where 
irv, to accommodate the control and bracing wires. 
A rib from the top center section, and one from the root 
of the lower wing, are both drawn to scale. See Fig. 1. 

The extreme thinness of the three-ply has given rise 
to a new method of fixing the flanges, on the ribs. In 
stead of grooved flanges tacked on so that the tacks run 
down the length of the three-ply, two half flanges of 
approximately square section are tacked together hori- 
ontally with the ply sandwiched between. 



Spars 

As may be seen from the various sections drawn to 
scale in Figs. 3 and 4, the spars are made up of fairly 
narrow flanges at top and bottom, joined on either side 
by thin three-ply webs. They arc placed approximately 
.So ems. apart. The flanges are made of Scots pine, and 
consist of two laminations. The three-ply has the two 
outer layers of birch and an inner ply which is probably 
birch also. 

The three-ply webs are tacked on to the flanges, and 
fabric is glued over the joint. The cement is an ordi- 
_'<-latine glue. 

The spar webs are glued to the flanges by a' waterproof 
casein cement, which is proved to contain gelatine, while 
the plywood adhesive also a casein cement is water- 



proofed and of sufficiently good quality to withstand four 
hours' immersion in boiling water. 

The trailing edge is of wire, and tape crosses from tin- 
top of one rib to the bottom of the next in the usual way. 
This tape lattice occurs about half-war between the trail- 
ing edge and the rear spar. 

Fig. 3 shows the sections of the front and rear upper 
plane spars, taken in the centre section and at the inter- 
plane struts, while Fig. 4 gives the corresponding lower 
spar sections. 

The ribs are stiffened between the spars by vertical 
pieces of wood of triangular .section. There arc two such 
pieces on each rib in the upper plane, and one in the lower 
plane. 

All the woodwork of the wings is varnished, and fabric 
is bound round the flanges of the ribs and glued to the 
top and bottom of the spars. 

The workmanship is decidedly good, and the finish neat 
and careful. 

Struts 

The struts are all of steel tubing of streamline section, 
and the centre section system is particularly worthy of 
attention. All those three struts which meet at a point 
on the front spar of the upper wing are welded to the 
fuselage framework, and arc thus not removable when 
the machine is dismantled (see Fig. 5). The strut which 
joins the rear upper spar to the front lower spar, how- 
ever, is not welded but is fastened by a ball and socket 
joint, which is the subject of Fig. 6. It will be noticed 
that the ball forms the extremity of n threaded bolt which 
is screwed into the end of the strut, thus making it ]>- 
sible to adjust the length of the latter. Both ball and 
socket are drilled and a bolt locked through the hole. 
The attachment of up|>er centre section struts to the wing 
spar is shown in Fig. 1. 

As is made clear in the scale drawings, the interplane 
struts are of X shape when seen from the starboard wing 



188 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Fig. 5- 




Fig. e. 




Hi. . 



fig. 7. 





Fig. 8, 




Fig. 10. 



Fig. 12 



KEY SWITCH 



PRESSURE CAUSES GREASE PUMP 



ACHTUNG; 

Hohengas* 



FROM AUXILIARY 

TANK jV 



^^ CAUTION 

,HI6H ALT. THROTTLE CONTROL 



AIR 

RELEASE COCK 

PUMP OFF 

PUMP 
.MOTOR PUMP 



TO'flUXILHRYY? 
TAM K 



Fig. 17 



Pig. IS. 




Fig. 16 



SINCJ.K MOTOKK1) A KKUIM.A \ I .s 



IH'.t 



tip. Till- tlircr mrlnllcrs of tin \ are w el, led together, 
and all four In-c extremities li;i\r tlir :uljiist:ili|i- attach 
inciit descrilN il abmr. It lias alrrailx IIIVM in. -iitinrii (I 

that tlnTf IN \tern.al hracing. tin win^ , ^instruction 

-ill^' in id.- surticicntlx strong against hit stresses |,, 
ohxiite its necessity, anil tin form of tin- mtcrplnnc struts 
is intcrestin:,' in this i-nnni-i-tiiiii. 

Fuselage 

This is exactly similar in design ami construction In tin- 
triplanc 1 o<lv allowing. >{ course, fur tin- difference 
in type of engine ami for tin- fart tli.it Ixith wings h.axe 
twn spars instead of one. Tin longerons and cross struts 
arc .it circular si-rtioii sli-rl tube wrlilril in plarr. and 
carrying it the corner tin small c|iiadrant of strrl tube 
wliirli cnrrirs tin- bracing. Tin- diameters of these tubes 
vary I rom M Minis, to IS nuns., and tin- strrl was of -2 \ 
gauge in tin- plans where tin- tnlirs had lirrn pirrrrd by 

bullets. 

This hr.-irini; wi II repays attention. All sides of ,-ach 
section an- cross liracrd with piano win-, which is simplx 
passed round tin two lugs to l- joined ami has its rv 
trnnities connected In means of a tnriiluicklr. This 
nirthod has tlir great advantage that only two loops are 
nired in tin- wire instead of four, and in consequence 
this bracing can lie very rapidly assembled. It is also 
possiHy lighter in relation to its strength than the usual 
amusement of single wire bracing. Fig. 8 shows how a 
handle is clipped on to the lower longerons. 

The front part of the body is a particularly good piece 
of welding, and includes the engine and radiator sup- 
ports a> well as the arrangement by which the continuous 
spar-, of the lower planes can be placed in position. This 
is dom by removing two fork-ended tubes (one each side 
if the body), and replacing these when the wings are in 
position. I i:,'. <> shows how the wing spar is joined to 
the fuselage and Fig. K) shows the fuselage joint at this 
point. 

Tin- cowling is of aluminum, and covers the front por- 
tion of the fuselage on all four sides. It is extended on 
the top to the cockpit, and underneath to beyond tin- 
rear spar. The cowls are arranged in convenient sheets, 
and an t istem-d by means of bolts and nuts of unusual 
The nuts ha\e small handles about 1 in. long, 
which enable on.- to manipulate them without tools. From 
. r half of the cockpit to the junction of the tail and 
Ixtdy. the top is furnished with a three-ply fairing, which 
xtends oxer not quite the whole width of the fuselage. 
This is shown in Fig. 1 1. 

Tail 

I In tixeci tail planes and elevators are almost similar 
to those of the triplane. i.e., the tail is triangular and the 
rs balaiierd and divided, although they are actually 
n one piece. The biplane, however, has a tri- 
angular Hn whose foremost point is fixed an inch or two 
to tin port sale of the centre line of the machine, thus 
proxiding a surface which is inclined slightly to the longi- 
udin-il axis of the aeroplane. This is illustrated in Fig. 
s is no doubt arranged to balance the tendency of 
'> machine to turn to the left in flight, due to the slip- 
in. 

I In framework of the tail is of circular section steel 
throughout, including the trailing edges, and this 



frnnn work is arranged to give the ti\ed tail symmetrical 
i tmbcr. The attachment of the tail plane to tin fuselage 
U simple and etl'r. In \ -, m t| lr trip! 

the top longeron-, arc dropped at this p.. ml sutlicnntly to 
allow the tail plain to haxe its top surface Nxi I with 
the top of the fuselage, and lime bolts passing through 
the main steel tube of the tail ami through short piece* 

ot tube welded to the |MI<|\ framework secure It il, this 

' f the three l>olts, one is plan . I il nlliir side 

of the top of the fuselage on the front of the tail, ami one 
at tin end of tin body framework. Tin tail pi nn i 
at a slight angle of incidence about ML. dcgr. , s 
which is not intended to IK- adjustable, but which could 
easily lie altered by nn alls of a few washers ami longer 
(Milts. The tail is stay, (I by two streamline section steel 
struts, which connect tin rear lulu- of tin tail plane with 
the lottom of the sternpost. as is shown by the general 
arrangement drawings. These struts an not harlteil. 
1'rom the sketch of the tail skid (Fig. 1M), it will be 
i that this member is balanced at a point al>oiit one 
third of its length from its lower end. and that the slnx-k 
absorbing arrangement consists of two helical stec I springs. 

Undercarriage 

This is a feature of the machine which carries a distinct 
trace of British influence. The angle between the two 
limbs of the Vee is usually, in German aeroplanes, very 
obtuse; i.e., the two top points of attachment are widely- 
separated, while British practice leans towards making 
this angle fairly acute. In the Fokker the angle be- 
tween the struts is about 53 degrees. The section of the 
steel struts is streamlike in form, with major and minor 
axes of 65 mms. and 3-1 mms. respectively. The metal is 
SO gauge. 

The upper attachments of the undercarriage struts are 
of the ball and socket type, with a bolt through, similar 
to the interplane strut illustrated above. The junction 
of the lower extremities and the slot which allows for 
axle travel is clearly explained by Fig. I ^. The bracing 
cables, which connect the upper extremities of the front 
struts with the opposite lower ends, are attached in the 
usual manner to lugs welded on to the struts. It in inter- 
esting to note that in the crash which wrecked the ma- 
chine, one of these lugs has torn out a small piece of tin 
sheet steel of which the strut is formed, though there 
is no sign of fracture at the weld. 

The least usual characteristic of the landing carriage, 
however, is the provision of a small cambered plane sur- 
rounding the axle, just as is the case in the Fokker tri- 
plane. This auxiliary plane has been badly battered, 
and few details are available, but the sheet aluminium box 
which surrounds the axle remains. This box is rectangu- 
lar in section, and the edges arc riveted together on the 
upper side. It forms the main and only spar of the plane. 
the construction of which is \er\ similar to that of the 
main plane. Tin- shock ahsorlx-rs are of the coil spring 
type, and are wrapped in the manner illustrated in Fig. 
lY The wheels are 760 X 100. 

Engine and Mounting 

The engine is a Mercedes of 1HO h.p. A full report on 
this type of engine has already been issued, but the pres- 
ent example possesses one or two minor points of differ- 
ence from the standard. The chief of these is the fact 



190 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



that this engine has domed pistons, giving higher com- 
pression. 

As has already been mentioned, the engine bearers are 
steel tubes, supported on a steel tubular structure welded 
up integrally with the fuselage frame and with the centre 
section struts. The diameter of these two parallel tubes 
is 34 mms. and the gauge 14. Each tube carries four 
" pads " of the type shown in Fig. 15, to which the crank- 
case is bolted. 

Radiator 

The radiator, as may be gathered from the scale draw- 
ings and sketches, is of the car type (another departure 
from modern German design), and is supported by steel 
tubes which are part of a fuselage frame. The radiating 
surface is surmounted by a curved fairing, of which the 
port-side half is a brass water tank, into which the filler 
leads, while the starboard side is merely an aluminum 
fairing. The radiator is constructed of brass tubes ar- 
ranged parallel to the engine crankshaft. The tubes are 
circular in section, but expanded into hexagons at either 
end and sweated up there. Each hexagon measures 7 
mms. across the flats. 

The single shutter, as will be seen on reference to Fig. 
16, is normally held open by a spring, but can be closed 
at will by pulling a small cable. This shutter even when 
completely closed only puts out of action a small por- 
tion (roughly about one-third) of the cooling surface. 

Petrol and Oil Systems 

There is only one fuel and oil tank in the machine. 
It is of sheet brass and is slung from cross tubes clipped 
on to the top longerons, just in front of the ammunition 
magazines, which are placed immediately in front of the 
pilot. 

So far as can be ascertained from such external evi- 
dence as is afforded by fillers, piping, the lines of rivets 
on the tank, and the gauges and petrol cocks, it may be 
said that this tank is divided into two petrol tanks and 
one oil tank. The main petrol tank has a capacity for 
61 litres .(approximately 1 sy 2 .gallons), and is provided 
with a baffle plate. The reserve tank holds 33 litres (ap- 
proximately 7*4 gallons), while the oil tank carries' 4% 
gallons. From the brass disc which is sweated to each 
flank of the tank, it would appear that a tie rod passes 
across the tank from side to side. Both petrol tanks work 
under pressure, obtained initially by hand-pump, and main- 
tained by the usual mechanical air-pump. The dashboard 
carries, besides the main switches and a starting magneto, 
a two-way cock which allows the pilot to use petrol from 
the main or auxiliary tank, or to shut it off completely. 
A separate pressure gauge for each tank and two two- 
way air pressure cocks are also mounted. 

Throttle Control 

A sketch of the throttle lever, situated on the pilot's 
left, is given (Fig. 18). This lever actuates the car- 
buretor throttle by the means shown. The compression 
tube between the quadrant and the balanced lever is over 
four feet long and about five-eighths inch in diameter. 
Although heavy-looking, this control is, of course, made 



of very light gauge material. The adjustment provided 
at the pilot's end of the control should be noticed. The 
control works in conjunction with a Bowden type lever 
on the control lever, as shown by Fig. 19. The twin 
cables from this auxiliary throttle lever are attached to 
the main throttle control Fig. 18 shows the attach- 
ments. 

Controls 

The control lever of the machine works on precisely the 
same system as that of the triplane, but the grip at the 
head of the column is quite different. Reference to Fig. 
19 will show that the usual two-handed grip is replaced 
by a single handle for the right hand. 

" The left hand is free to manipulate the auxiliary throt- 
tle control, inter-connected with the main throttle lever. 
It should also be noticed that the usual pushes for firing 
guns are absent, and the interrupter gear is actuated by 
pulling either or both of the levers by the fingers, while 
the thumb rests on the specially arranged place. There 
is no separate arrangement for firing both guns together, 
and it is not possible to lock the elevator controls in any 
given position. 

The longitudinal rocking shaft carries at its front end 
two arms to which the aileron control cables are fixed (see 
Fig. 20). These wires cross; and pass upwards and out- 
wards to aluminium pulleys on ball bearings, which are 
attached in pairs to a hinged sheet steel framework. Or 
the way these cables pass through short tubular guides 
fixed to the top longerons. The aileron levers follow con- 
temporary British practice, and project vertically above 
and below the plane. 

The elevator control wires are taken direct from the 
control lever, one pair above and one below the fulcrum 

The rudder bar (see Fig. 21) is of neat and light weldec 
construction. There is no adjustment to allow for varia- 
tion in leg-length of different pilots, but it should be no- 
ticed that the pilot's seat is adjustable as regards height 
The means by which this movement is obtained is exactb 




Fig. 19. 



Control details of the Fokker D-7 



SINtil.K MOTOKK1) AKUOl'l \\|> 



1JH 



In same as the arrangement in tin- triplanc. i.e., the seat 
> a sheet aluminium liuckt I uilh .1 three ply bottom sup 
lorted by a framework ol st.,1 tubes which grips the 
_re cross struts In fnur clips, which c.-in In- placed 
it any height. '1'his i-. in.-iilc clear by 1 'i^. 

Fabric and Dope 

The f.-ihrie is nut attached in any w:iy In the longerons, 
nit is simply carried oxer tin- fuselage and laced ahnii: 
he bottom centr.-il line. There is .1 cross-piece of fabric 
aced to the cross tubes immediately behind the cockpit. 

The fabric is coarse flax, coarser and less highly eal- 
ndered than the type usually met with, and a good deal 
leavier. 

It is colour printed in the usual irregular polygons. 
The bright red paint, mentioned below, is removable by 
ilcohol, but not soluble in it, coming off ns a skin under 
reatment. 

I'nder the paint is a dope layer an acetyl cellulose. 
Siit In r paint nor dope presents unusual features. 

Wrights 

I'. lint !).'.() (fins. |MT s<|. m. 

Dopr (iM.l (fins. JUT s(|. in. 

I al.ric I i:Ui (rins. |-r scj. m. 



mr.{.7 |rms. per sq. m. 

SI ri-n jtth 1779 k in. 

Kxtriisinii 7.0 jx-r cent. 

\Vhere the wiiiys are not painted, the fabric is covered 
vith a linn layer of dope only. 



Schedule of Principal Weights 

Ib*. oc. 

I |'|MT wiii(f, fiiinpletr with .nl. r,, u-. jiiillrys brwinp 

irr>. falirir and strut litlinjfs ! \M 

1 OMIT win); (mi ailerons titled), complete uilh strut 

littiii|r< and falin- - 97 

N I rut IH-IUIVII winj-s | > 

Str.ii^'lit strut. U-twiiii fiis,-|.i L . r and trHilliifr spur of 

upper winy * 8 

\ilenill Ir.iin.-, with hilife flijls, witlioilt f.iliri. 4 8 

It udder frame, with \\ii\fr clips, witlxinl fnlirir 4 II 

I in fr; . M ith<iiit fnl>ric 1 14 

Tail planes (eninplet. 111 .me plrcr), without fabric... li 6 

I kvntors (complete In one piece), without fnhrlc II 9 

It.iiii itur einptx l> 

I 'ndrrcarriafre strut, each 2 10 

riulrrcarrUfre \lr, with shock itltsorlirr lioblilnk 1H 8 

Uol.liin. each " : 

Sh<K-k ahsorlK-r. each : 

t'lidrrcarrlaire (complete ), without wheel* *n<l tlre, 

and without plane, hut including struts *> 4 

Aluminum tuhe. forming rear spar of undercarriage 

plane 1 8 

Wheel, without tire and tube II 8 

Tire and tube 9 4 

Tail strut I 13 

Fabric, per square foot, with diijw 1 

Bottom plane compression rib 15 

Itottom plane ordinary rib U II 

Top plane ordinary rib. at centre of plane 1 

Bracket, with holts, attaching top plane to fuselage 

struts 1 II 

Main spar, top plane, including fillet for ribs, per foot 

run in centre 1 11 

Owing to tapering ends the average weight per foot of 
the spars will be slightly less than this figure. 



The Tarrant " Tabor " Triplane 




Tarrant "Tabor." equipped with six \apier "I. ion" rnvines of .VN h.p. each. Spnn of tin- middle plane is 1:11 ft. : in. 
Overall height is :7 ft. : in. Overall length. 7:1 ft. .' in. Total weight. 45,000 pounds 



192 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Gunners Sea 



Pilots Seat. 



HALBERSTADT 
GENERAL DETAILS 
Two-Sealer Biplane 

Span 35' 3}' 

Gap 4'0'to3'8J' 

Chord Top Plane 5' 3i' 

Chord Bottom Plane 

Overall Length 

Tail Plane Span 

Height 

Engine 

Set Back of Planes 

Propeller 9' o' 

Track 6' 4' 

Stagger 2' o' 



4" 3J- 
. 24' 0* 
. 8' 11* 
9' 6' 
. 160 h.p. 
4 




PLAN DRAWINGS OF THE HALBERSTADT FIGHTER 



The Halberstadt Fighter 



This German machine is a two-seater fighter. 

General Details 

Bristol Technical Department has stated that the Hal- 
berstadt represents, in all probability, the high-water 
mark of two-seater Germa.i aeroplane construction, as it 
is not only well and strongly constructed, but its general 
behaviour in the air is good according to modern fighting 
standards. 

Span of upper plane 35 ft. 3</i in. 

Span of lower plane 34 ft. 11 in. 

Chord of upper plane 5 ft. 3'/ 4 in. 

Chord of lower plane 4 ft. 3'/., in. 

Gap, maximum 4 ft. 

Gap, minimum 3 ft. 8y 2 in. 



Dihedral angle of lower plane 2 

Horizontal dihedral of main planes 4 

Total area of main planes 310 sq. ft. 

Area of each aileron 1 l.S sq. ft. 

Area of aileron balance 2.0 sq. ft. 

Load per square foot 8.2 Ibs. 

Area of tail planes 13.6 sq. ft. 

Area of elevator 12.4 sq. ft. 

Area of fin 6.4 sq. ft. 

Area of rudder 7.9 sq. ft. 

Area of rudder balance 1.0 sq. ft. 

Maximum cross section of body 8.8 sq. ft. 

Horizontal area of body 44.0 sq. ft. 

Vertical area of body 52.8 sq. ft. 

Length over all 24 ft. 

Kngine 180 h.p. Mercedes 

Weight per h.p. (180) 14.0T Ibs. 



SI\(,I.K MOTOKK1) .\KHOIM..\\1 - 



I'.t.'i 



Schedule of Principal Weights 



Tolnl 



! 



Capacity of |)rtrul tank- :| . ,11,, us 

C.lp.inU "I oil Link- I i;'lll"!l- 

Crew I'wn 

(inn- I t>\iil .mil 1 inovHlilr 

Militant hud en t.-xt . I. His. l l'l"' r wi "(f. -iiinp|rlr uith .ol.r .iili-r.iti r(Ml. ilmg 

io.ul on tot '..,.' II.- ''-' ""' ' >lrut attachments, hut without lid 

liruriiiir wirrs ,n,l tabfi . / 

Performance I "-T iiic. .1* .il>m.- < no aileron nttrd) . a - 

\ilrnm ( <nn|ilrtr. without fnlirir . 

S -'(I .'it IO.OIMI ft.. !7 ni.p.h.. l.is:> r.p.m. \ili-rnn Imr, wilh flnnp- 

It,., otrii.nl, Indicated |"|"I'|H- *ru. '-,.. .,i| H ,,,t 

Mi.,. inf.. nun. Airspeed .'"7 '" ; tr " '"*'"' '"'; : ' 

Cli.,.1, to .'..I" N. ft. llu N "'I' 1 ''''-' ttlth '""I'T ,Ml itr.vlty 

rii.,,1. I ,000ft MO -,l .<-...( r.,1 ,. rank .n,M-rcln K wirrx .101 

CUmb to 14000 fl ,1 53 BO H-" l'l |-lm- (rrh). with fJ,rk . T 8 

Rodder, complete iih fhri<- .78 

, Kli-vatdr. coinplrtr, with Mngr dipt and faltrtr I ' 

Serrto .,-.l.,. K (lu-.^ht at wind, ,-l.mb is 100 feet ,HT Hni ,,,,,,..; wi ,' h f ., irlc 

, 13,500 ft. ,irr M-rtion >trul . .97 

aliMiliitr i-riliiii;, Ili.OOO ft. Straijrtit orntrr x-i-tinti slrul 3 i^ 

(.r, .it.xt hci.nlit r.adi.d. U.SOd ft. in IU ininiit. -, K> rnilrrrarrla((r. rcmiplrtr wilh >trut and l.r.rin K , 

. ( j s whrrN, tyrr-, mill shock aliMirlirrs I0i 

Sliix-k hvirl>rr (innltipli- mil priii)r t\pr).rarh .... 4 

Stability and Controllability Z!**L? *""*'" *"'"'"" **** 

\\ ncrl, w ii n IV FT . o 4 

Hat, of ,.,,, a, IU. height, , f,,t ,,, r .inute. 31^-5 ^^S- ^ " 

!u> ina.-liMir caim..) be considered vteble. There is WinKS . trailing .,,,, r . ,HT foot run o 14% 

a tendency to stall with thr mjiine on, and to dive with 

tin- , iinin. ,,tl. Din .-tionallv. owing to tin- propeller Historical Note 

s,rl. thr ,,,;,,.|,i,,,. swings to the left, but with thr ni,{iiii- The pr.-s.-nt H.-,ll.,-rst,,lt fightrr is .-, <l.-i.-1pim-iit of the 

ls '" " tri1 enrlirr sin^l, s.-nter. an example of which wax brouglit 

!.rt th. m.-u-hi,,,. |jht and comfortal:], to fly. down on October ii<. I!IT. In th.- latt.-r ->e ash was 

'M.-.nralMlity is K O,H|. and this fraturc. tak.-n in lls ,.,| ,,, f, ir l v | nr)f< . ,. x t,., lt . U.th in the fuselage and 

njmu-ti,,,, with th.- exceptionally tin,- vi.-w ..f thr pilot will>INi f)llt in j| 1( . m ,, r( . ln , M j,. rn ( |,. s ^ n ,p riu .,. is ( . xo i u . 

bterra an,! thr h'.-hl of fire of the latter, makes thr siv ,.|v ...L.pted. Thr r.-.-ir spar was of thr ordinary ' 

irhin, oti,- to ! r.-.-konrd with as a " two s, at, r fighter." (ion type without three-ply rrinforerment. Thr fuselage. 

^h the climb and speed performances are poor ,,f somewhat similar shapr, was fabri, ,,,v- r,d. Balanced 

Hpd by ..-ntrmporary British standards. elexators and rudder were fitted, but no fixed tail plane 

or fin. Tli, arrangement of the centre section, with tank 

rincipal Points of the Design and radilllor> w;ls M1 | 1 , l . 1Iltia l| v . s m ,.. |, 011 |,i,. h.^, 

- _lr bay arrangements of wings. of interplanr struts were adopted, but thr struts tin m 

iiieuoiis set back of thr main planes. sdves were of the welded-up ta|-red pattern. The ailer- 

Bmpennage fre>- from wir,v ons were controlled by wires and not. as in the prrvnt 

I 'iisilage ta|MTs to a horizontal line at the rear in di- example, positm-ly. Both planes had the same chord and 

utradistinetion to the usual (,, rinin practice. the upper wings had an overhang. The weight of the 

Pilot's and observer's cock-pits constructed as one. complete machine without pilot was 17*8 Ibs. 



\ / i; 
_..,,_,,-..._.,--,. 





AUSTRIAN TYPE ALBATR05 

HAN5A BRANDENBURG 

^00 H-P FIGHTING TRACTOR 



MILLIMETERS 

ItOO tOOO I 



Mclaughlin 



194 



SINC.I.K MOTOK1.I) AEROPLANES 



The German Hansa-Brandenburg Tractor 



Tin- struts st.-iiifjercd outward at their lower rnd-. is a 
ttatiirc peculiar to this machine. Many of tin- Albatros 
features art 1 sci n in this machine, together with a mini 
lx-r i>f original and unique fittings. Tin- accompanying 
drawing-, show a side and front vii-w and a plan vn 
from In-low . 

General Dimensions 

Sp.m, ii|i|irr plane l-.i40 nun. 

Span, low IT plain- II. 7 .'n nun. 

Cliortl. I .illi planes l,7i:l nun. 

Area, iipprr plain- ^."70 M). ini-lrr-.. 

Area, lower plain- 1,790 v|. meters. 

(l.ip lu-twt-cii planes 1,7 l:i nun. 

(Kcrall hcicht ..I I 'nun. 

Overall length 8,370 mm. 

M,.t..r. \V.ir-k:ilowski **> h.p. 

Planes 

Plain-, arc in four sections two upper and two lower. 
l'|i|n-r pi. me M -etions joined at tin- top of a cabane formed 
of steel tube :io liy Hi mm., with lower ends terminating 
in fittings attarln-d to tin- upper longerons of the fuselage. 

F.ach upper plane section has an area of 1135 sq. meters. 
F.ach lower plane section has an area of 895 sq. meters. 

Ailerons are attached to subsidiary steel tube spars to 
the rear of the main wing beams. Attachment is made 
with a fitting of sheet metal and soft wood blocks, with 
tiler to take up the wear. Kach aileron has five such 
hinges. Ailerons each 2850 mm. long. 

Wing beams arc cut in two vertically, hollowed for light- 
ness and mortised together with hardwood strips. For- 
ward .spar varies from 70 to 72 mm. in height and the 
rear spar the opposite; both are 85 mm. thick. 

Filtering edge is curved to a diameter of Ml mm. Front 
spar centered 100 mm. from leading edge. Wing spars 
SIMI mm. apart. 

Halt. us are ->.:> thick and 13 mm. wide. Webs 45 mm. 
thick, cut away for lightness to within 15 mm. of the 
battens. Light veneer strips. 12 mm. wide, reinforce the 
weds between lightening holes. 

The interplane struts are of 32 mm. diameter steel tube 
with their ends terminating in eyes for attachment to the 
strut sockets. Hollow wood fairing strips are bound to 
tin- rear of the strut tubing, giving it a streamline form. 
and bringing its width to 126 mm. Each end is attached 
by an s mm. bolt. Lift, landing and incidence cables 
vary from 5 to 7 mm. in diameter. 

Fuselage 

Overall width of fuselage, 1020 mm. From the for- 
ward engine plate to the rudder, the fuselage is 7180 mm. 
long. A formed cap fits over the forward engine plate, 
and the propeller shaft goes through it. Four sheet metal 
engine plates carry the two 50 by 100 mm. engine bed 
rails. The longerons are solid, 80 by 45 mm. at the 
front, the lower pair tapering to 19 mm. square and the 
upper pair 17 mm. square. 

The pilot's seat is set in a recess formed at the top of 
the main fuel tank. Overall dimensions of the tank 
top 300 by 820 mm. ; bottom "OO by 82(1 mm. ; height 650 
mm. The back forms a right angle with the top and 



liottoin and the forward end slopes down from the top. 
A recess 1711 nun. .|,.|.. 71111 .mn. long and t?(l mm. w nit- 
is proxided for the seat. Seat :>.MI mm. long and UO mm. 
wide, rcsimg on n pair of iron bands ~ :. mm. thick and 31 
mm. wide, which encircle the tank. A tilling tulx- runs 
up at the rear of the tank, mar the .side, with n :> I nun. 
opening. 

A fixed machine gun is provided for the pilot, located 
on the upper plane. The ^miner's cockpit, at the rear, 
is provided with a movable machine gun clamped to a rail 
around the cockpit o|x-ning. 

Tail Group 

Tin- horizontal stabilizer is in one piece, resting on the 
upper longerons. The forward end is rounded off at a 
HIM mm. radius. Overall dimensions, 229(1 by .'!> M) mm. 
Surface at each side of body, 192 square meters. Tin- 
edges are of steel tube 20 mm. in diameter and the in- 
ternal structure is of 10 mm. diameter tulx-. It is sup- 
ported from IM-IHW l>y a pair of steel tubes of 25 by 13.5 
mm. section. Threaded eyes in the lower ends allow of 
their adjustment. Lower ends attach to lower longerons 
at a point 1860 mm. from the fuselage termination. 

Slots. GOO mm. apart, are provided where the flap con- 
trol cables run through the stabilizer. 

From tip to tip the elevator flaps measures 3500 mm. 
Maximum width, 670 mm. Kach flap has an area of 83 
square meters. Edges are formed of 15 mm. tube, and 
outer tips curved to a 120 mm. radius. 

Flap hinges are of sheet metal, soldered to the 25 mm. 
till" of the flap and stabilizer. Fiber blocks between the 
tubes space them 10 mm. apart, and take the friction of 
the flap movement. 

The vertical fin is triangular, 700 mm. high and 13OO 
mm. wide. The rudder is l<>'>(> in overall height. Width 
at rear of pivot, 670 and width forward of pivot (the 
balanced portion) 340 mm. Forward edges curved to a 
30 mm. radius, and trailing end to a 110 mm. radius. 
Two hinges attach the rudder to the fin. The control 
lever is of solid steel, and it spaces the control wires 117 
mm. apart. 

Landing Gear 

The axle is of steel tube, 54 mm. outside diameter. Mi 
mm. inside, located at a point 1680 mm. from the front 
of propeller hub. Landing wheels are 770 mm. in diam- 
eter by KM) mm. wide, and centered 2070 mm. apart. 
Two sections of streamline fairing are bound to the axle, 
and a claw brake between them. 

The brake is 730 mm. long; 230 mm. forward of the 
axle and 5OO mm. to the rear. The claw is 145 mm. in 
length, and the brake is operated by a cord from the 
pilot's seat. 

The chassis struts are of 70 by 35 mm. tube. The for- 
ward pair is faired with streamlining to a total depth of 
120 mm. A peg is located half way up both of these 
struts as a means of mounting to reach the motor. At the 
lower end of chassis struts, the shock absorbing elastic 
cords are bound. Grooves keep them in place and a 
leather strap, strung from forward to rear struU, limits 
the upward movement of the axle. 




Details of the Hansa-Brandenburg Tractor 
196 



SI\(.I.K MUTOKKI) AKKOl'I.AM - 



197 



Details of the Austrian Hansa-Brandenburg Tractor 

'< 




One of the i lrv.il, ir rontrol levers 




Rear attachment of tin- tnil plain- to (lie fuselage 




Tin- tn fnrwar<l engine plates 





Strut fitting t the 
front -.im r, upper left 
wlnjf 




I runt, side and top views of the main fuel tank, upon 
whioh tin- pilot's seat is plared 




Aileron and tail flap or 
stabilizer hinges 




Ix)wer end of the brace from the 
tall plane to the fuselage 



198 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



I 'I 'I '"I 1 I'l ' I '1H 'i 1 i> t' i't 1 liU'Hji 1 VH 




The Wittemann-Lewis Commercial Biplane 



The Wittemann-Lewis Aircraft Company Model " F. A. 
2 " is the result of careful planning for a commercial 
airplane by the Messrs. Wittemann, and built to the design 
of A. F. Arcier, A. F. R. Ae. S., formerly chief engineer 
of Handley-Page, Ltd., and now chief engineer of this 
Company. 

The principal features of the machine are the unusually 
low landing speed, the large capacity and sumptuousness 
of the body, and the comparatively small space in which 
it may be housed by folding the wings. 

Wings: The upper wings are composed of three sec- 
tions, the lower ones of four. The outer sections hinge 
back by simply removing four pins, when in the folded 
position they clamp back against the fuselage. The spars 
are I section spruce and the ribs special built up. The 
interplane struts are spruce. The main spar clips are so 
designed that they set up no additional bending mo- 
ments. 

Body: The L. C. Liberty motor is silenced and is 
mounted on ash beams supported by tubular construc- 
tion. The whole power unit comprising: Propeller, 
Radiator, Motor and Tanks, is removable in one unit by 
undoing six bolts and disconnecting the control and instru- 
ment leads. Risk of fire is reduced to minimum by fire- 
proof bulkheads and by suitable placing of carburetors in 
fireproof compartments. 

Reliability of the motor is assured by reducing its maxi- 
mum output and by gravity fuel feed. 

The cabin is approximately 5' 6" x 4' x 9', giving 170 
cu. ft. of unobstructed space, and has seating capacity for 



four passengers comfortable swivel arm chairs and a 
folding table are provided. The exhaust heating and the 
ventilation can be adjusted by the occupants. The en- 
trance to the cabin is large and within stepping height of 
the ground, making the machine as easy to enter as the 
average automobile. 

Pilot has unobstructed view and is seated aft of the main 
loads. 

Landing Gear: The landing gear has an exceptionally 
wide track, making overturning impossible, long travel 
shock absorbers are fitted and a dashpot provided to pre- 
vent rebound. These precautions together with the low 
landing speed make the machine very safe and easy to land. 
The tail skid is steerable on the ground to facilitate 
ground manoeuvring. 

Controls: A " Dep " arch is provided, and the rudder 
is operated by foot pedals. The tail is adjustable in flight 
for varying loads. 

The disposition and size of the controlling surfaces are 
such as to assure a large degree of inherent stability. 

Area: Top plane, 3S3 sq. ft.; lower plane, 306 sq. ft.; 
ailerons, 92 sq. ft. ; tail plane, 70 sq. ft. ; tail flaps, 20 sq. 
ft.; rudder, 12 J /6 sq. ft.; fin, 8 sq. ft.; chord both planes, 
6 ft. 9 in.; gap, 6 ft. in.; span, wings extended, 52 ft. 
in.; wings folded, 22 ft. 6 in.; o. a. length, 35 ft. 1 in.; 
o. a. height, wings extended, 11 ft. in. ; o. a. height, 
wings folded, 9 ft. 9 in.; weight full, 4,040 Ibs. ; useful 
load, 1,650 Ibs; loading 6.33 Ibs. per sq. ft.; duration 
(cruising), 4'/ hours; landing speed, 35 m.p.h. ; top speed, 
105 m.p.h.; ceiling, 15,000 ft.; climb, 10,000 ft. in 30 min. 




ROLAND D.n. 

16O H.P 
MERCEDES. 



I : 

1cK- wop " 



The Kolml Sin^k--.tcr Ch^er D.ll. PUn, W<- .nd front elethm. to 

11)0 



200 



TKXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Starboard quarter view of the 
lioland D.II. chaser 



The Roland Chaser D. II. 



The dimensions of the Roland D. II are very small: 

Span of upper plane 8.90 m. 

Span of lower plane 8.50 m. 

1 .ength overall 6.95 m. 

Height 2.95 m. 

Its weight 827 kilogs. with full tanks is slightly 
greater than that of the Albatros D.III chaser. The lift- 
ing surface being 23 sq. m., the wing loading is 36 kg./sq. 
m. (7.2 Ibs./sq. ft). 

Fuselage 

The construction of the fuselage, and its peculiar shape, 
merit special attention. Being built entirely of three-ply 
wood and covered with fabric, it is of the monocoque type, 
of oval section, and terminates at the stern in a vertical 
knife edge. The construction is excessively light, the 
framework consisting of very thin longerons running 
through the whole length of the body, the curves of which 
they follow. Rigidity is only provided bv the ply wood, 
made in two halves joined along the middle of the top 
and bottom. The total thickness of the six layers is only 
1.5 mm. From the pilot's seat to the tail there are only 
four formers of very small thickness. 

Between the pilot's seat and the motor the fuselage 
forms a projection tapering upwards to form at its upper 
extremity an edge 0.11 m. wide, to which are attached 
the radiator and the top plane. The top plane is cut 
away to accommodate the radiator. This arrangement 
of an upward projection of the body itself takes the place 
of the cabane. On the lower part of fuselage, and built 
integrally with it, there are the rotts to which the two 
halves of the lower plane are attached. At the rear the 
tail skid, of wood with a shoe of metal, pierces the fuse- 
lage, and is supported on a projection of ply wood similar 
to that employed on the Xieuport. 

The pilot is placed very high, and has in front of him 
two wind screens, one on each side of the central struc- 
ture carrying the upper plane. 

Planes 

The planes are of trapezoidal plan form, of unequal 
span, without stagger and dihedral angle, but with a sweep- 
back of 1.5. The chord, which is uniform, is 1.45 m. 
and the gap 1.3-1 m. The ribs are at right angles to the 
leading edge. As the inter-plane struts are secured to 
the spars over the same rib, it follows that in the front 
view the struts do not come quite in line. The spars of 
the upper plane, which are of spruce, are spaced 0.83 m. 



apart, the front spar being 0.13 m. from the leading edge. 
The ribs, of which there are 12, are of I section with 
flanges of ash. They are spaced about 0.37 m. apart. 
In the middle of each interval there is a false rib running 
from the leading edge to the rear spar. In each wing 
there are four compression members in the form of steel 
tubes 25 mm. diameter. These tubes are evenly spaced, 
the distance between them being 1 .30 m., and are braced 
by 3 mm. piano wire. Between the front spar and the 
leading edge there are two tapes running parallel to the 
spars and crossing alternately over and under consecutive 
ribs. Two more tapes are similarly arranged between the 
spars. Certain corners are stiffened by reinforcement by 
ply wood. Each of the upper planes carries an aileron, 
which is not balanced and of equal chord throughout. A 
strip of three-ply wood, under the fabric, covers and pro- 
tects the hinge fixed on the rear spar. The aileron meas- 
ures 1.82 m. in length and has a chord of 0.42 m. Its 
leading edge is a steel tube of 30 mm. diameter. The 
aileron cranks are operated, as in the Nieuport, by two 
vertical tubes. In the left top plane is mounted a petrol 
service tank. 

The lower planes are constructed in much the same 
manner as the top ones. The spars are similarly arranged 
and are consequently the same distance apart. In each 
wing there are 10 ribs, of which nine measure 0.01 m. 
and the last one 0.025 m. Between the ribs are false ribs 
measuring 10 mm. The internal wing bracing is the 
same as that of the top plane, but the distribution of the 
four steel tube compression struts (of which one is 20 
mm. and the other 25 mm.) is somewhat different. From 
the first to the second is 1.17 m., from the second to the 
third is 1.13 m., and from the third to the fourth 1.11 m. 
The lower planes are attached to wind roots built in- 
tegrally with the fuselage. The angle of incidence is 4 
at the second rib and 3 at the seventh. The interplane 
struts are in the form of steel tubes 0.025 m. diameter, 
stream-lined with a wood fairing which brings their depth 
to 0.09 m. 

The Tail 

The shape of the tail can be seen from the plan view 
of the machine. The fixed tail plane is built of wood, 
while the two elevator flaps are constructed entirely in 
metal. 

A note should be made of the attachment of the tail 
plane to the body. The leading edge of the tail plane is 



SINCl.K MOTOHI.I) AKUOl'I.ANK.s 



-in 




II. II..I...:! D.I I. ,.|r,s,. r . (1) 



of "bump" supporting top plnnr nml radiator. (.') <Juick-rrlcn>e l>olt for HttH.liinif main 
planes. (3) I'pprr plane. (4) One of the miiln plane rllw 



hollowed out. and into the hollow space thus formed fits 
n piece of wood which runs across the fuselage and the 
ends of which project (1.50 m. on each side. Further 
rigidity is uivm to tin structure by two stream-line tubes 
runnitifj from the tail plane to the rudder hinge on the 
I fin. The rudder, which is roughly rectangular 
with round, (1 corners and has a forward projection for 
l''il.-incing. is built up of steel tubes, while the fin. which 
is made integral with the body is of three-ply wood. 

Engine 

The engine fitted on the Roland D. II is a 160 h.p. 
(lea six-cylinder vertical engine. The exhaust col- 



Irctor is nearly horizontal, and is placed on the starboard 
side. In addition to the gravity tank in the top plane 
there is a main gasoline tank measuring 70x70x25 un- 
der the rudder bar. The airscrew has its boss enclosed 
in the usual " spinner." 

Undercarriage 

The undercarriage is formed by two pairs of Vee struts, 
braced diagonally by two crossed cables. Their attach- 
ment to the fuselage occurs at two sloping formers. The 
axle, which is placed between two cross tubes, is enclosed 
in a stream-line casing. The track is 1 .7.1 m. The wheels 
measure 700 by 100. The shock absorbers arc of rubber. 



Siile view of the fusehjre of the Roland 

IHI rli.'isi-r. Tl mil siw of this 

111:11 -liinr is apparent from the picture. 




20-2 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Comparative specifications of the L. V. G. biplanes 
C.II., C.IV., C.V., and Rumpler C.IV.: 







L.V.G. 




Rumpler 


Span (upper wing) 
Span (lower wing) 
Total length 
Height 


C.II. 

12.85m. 
11.35m. 
8.10m. 
3m 


C.IV. 

13.60m. 
13m. 
8.60m. 
3.10m. 


C.V. 

13.62m. 
13.85m. 
8.10m. 
3.90m. 


C.IV. 
12.60m. 
12.10m. 
8.4m. 
3.25m. 


Lifting surface . . 
Weight 


37.60sqm. 
845kg. 


40sqm. 
900k g. 


42.70sqm. 
930kg. 


33.50sqm. 
1,010kg. 


Power of motor . . 
Make of motor . . . 


175h.p. 
Mercedes 


235h.p. 
Mercedes 


225h.p. 
Benz 


260h.p. 
250h.p. 
Mercedes 
or Maybach 



Note 1 metre = 32.37 inches. 

1 sq. metre = 10.75 sq. feet. 
1 kilogramme = 2.2 Ibs. 

The L.V.G. type C.V. is a two seater. It belongs to 
the " general purpose " class. 

Less speedy on the flat than the Rumpler C.IV., its 
rate of climb is inferior (4000 metres in 35 minutes), and 
equally its ceiling is less elevated (a little more than 
5000 metres). 

Its speeds are as follows : 

At 2,000 metres 164 km. per hr. 

At 3,000 metres 160 km. per hr. 

At 4,000 metres 150 km. per hr. 

The Wings 

The upper and lower wings are set at a dihedral angle, 
more so the lower ones. 

This dihedral is of 1 to the upper wings and of 2 
to the lower. They are neither staggered nor swept back. 



Front view of the L.V.G. biplane: type C.V. 

The L. V. G. Biplane Type C. V. 

The trailing edges of the wings are flexible. The ribs 
are spaced about .4 m. apart, with false intermediary ribs. 
The incidence of the wings is as follows: 

At 1st and 2nd ribs 4.5 

At 3rd to 9th ribs 5 

At 10th rib 4.75 

At llth rib -I -5 

At 12th rib 4 

At 13th rib 3 

The upper wings, viewed in plan, are slightly trape- 
zoidal, with rounded edges. 

Their chord is 1.74 m., and in the centre a semi-circular 
piece is cut out of the trailing edge above the pilot's head. 

The ailerons project past the ends of the wings by .84 
m. Their form is rounded, and resembles that of the 
ailerons of the Gotha. Their total length is 2.61 m. 
Their chord varies from .53 m. inside to .75 m. at the 
projecting portion. 

The hinges of the ailerons are parallel with the lead- 
ing edge of the wing. They are attached by means of 
pins or bolts threaded through hinge loops, held in place 
by keys, on the system employed to attach the ailerons 
on the Roland fighter D.II. The arrangement has the 
advantage of permitting the quick attachment of the mem- 
bers. 

The lower wings, following the present tendency of 
German aeroplanes are rounded at the ends and taper at 
the rear, as in the D.F.W., Rumpler C.IV., and Albatros 
C.IV. Their maximum chord is 1.59 m. 

The aileron cables pass through the interior of the 
lower wings. 

The interplane struts (two pairs on either side of the 
fuselage) are constructed of streamline timber 105 m. in 




Rear view of the L.V.G. biplane: type C.V. 



S1NCI.K MOTOKK1) A I .K< >1'L.\ M .x 




\ \ii-w nf 



tail inrnilirrs 



(lianu-tcr. and t.-ipiTnl towards Imth i-iuls. Bv reason of 
tin- differing dihedral of angles the inside and outside 
struts :irr not thr same length. 

Tlii- outer struts are 1.6.S5 m. long and the inner ones 
I.:.!" in. 

Tin gap between thr wings is 1.71 m. at tlie fuselage 
.-iixl I t'lii in. in linr with thr rxtrrn.il struts. 

Thr total lifting surface is i j ;i M |. m.. that of the up- 
per plain- hriii^ -.':!. 7S sq. m., and the lower 19.17 sq. m. 

Tin- rah.-nir struts an- in thr form of an " N." inclined 
towards tin- ri ar. and converging to the fixed centre sec- 
tion of thr upper plane, tin- width of which is .IS m. 

The Tail 

Tin- sh.-ipr of tin- stabilizing plane, or fixed tail plane, 
resembles that of the Albatros fighter. 

Thr tail plane consists of two separate parts attached 
our on each side to a fixed section embodied in the fuse- 
which like it is constructed of three-ply. 

Thr elevator is a single flap, with rounded corners and 
balanced by a triangular extension at each end. The 
test width is :i.(H m. and the depth .65 m. The small 
triangles have a base of .39 m. and are .39 m. high. 

At the outer angle of each of the tail planes one finds 
a projection of about .040 m.. intended to eliminate vi- 
bration from the tips of the balanced ends of the eleva- 
tors by screening them from the air blast. 

The balanced rudder is placed above the elevator, and 
forms with the fixed fin an oval inclined backwards. 

Tin- fixed fin is constructed of -three-ply, and is trape- 
oidal in shape. The total height of the vertical empen- 
nage is 1.068 m.; its depth is .675 m. (1.15 m. including 
tin compensated portion). 

The internal structure of these members consists of steel 
tube-work. 

The control cables pass through the fuselage, coming 
outside l.."i() m. from its extremity; one pair of the ele- 
vator cables pass through a channel in the thickness of 
the stabilizing plain . 

The fuselage is entirely built of varnished three-ply, 
and is rectangular in form, with a well-rounded top. the 
uiuii rside being slightly less rounded. The sides have 
a slight outward bulge, accentuated at the level of the 
pilot's seat. 

The Power Plant 
The I..V ( . i \ . is driven by a Garuda airscrew, type 




A view of the rvlmiist in.iiiifoM 

V., with a diameter of .S.oi m. The boss of the airscrew 
is enclosed in a " Casserole," or pot. .58 m. diameter. 

The motor is a 225 h.p. Hen*, also used in the D.I \\ 
and F.1XH.G. II. 

It is fed by two tanks, with a capacity of 249 litres. 
On the upper left wing is fitted a feed tank. The con- 
tents of these tanks permit of a flight of almut 3' , hours. 

Tin up|M-r portion of the motor is entirely covered in 
with a panelled and removable sheet steel bonnet. 

The exhaust is led overhead as in the Kumpler ('. IV. 
Contrary to that machine it is not much curved, but rises 
nearly vertically. 

The honeycomb radiator, the capacity of which is 35 
litres, is placed in front of the wings. It is rectangular 
in shape, and is attached to the eabanc struts by two 
brackets. Its upper part is attached to the fixed centre 
section of the upper plane by a small steel tube fork. 

Tin temperature regulating blind placed in front of 
the radiator is one of the best in use. It is simpler and 
more rational than the system of shutters. It consists 
of a movable blind of strong fabric, which is rolled and 
unrolled at the will of the pilot, which permits the stop- 
page of the passage of air and the regulation of the cool- 
ing. 

Accommodation 

The accommodation for the pilot is of oval form, the 
bigger dimension being in the direction of travel. 

Very close to this is arranged the passenger's seat in- 
side a turntable .86 m. in diameter, which carries a " Para- 
belltim " machine-gun. 

In front and on the right side is a Spandau machine- 
gun firing through the airscrew, and controlled by a Bow- 
den wire. 

Wireless apparatus is installed. 

The landing carriage consists of two pairs of streamline 
" V " struts built of timber, and a pair of wheels 810 
mm. x 1 '2!> mm. 

The wheel track is 1.98 m. The axle is placed in a 
streamline wooden fairing. 

As in the Rumpler ('.IV., a drag cable runs from tin- 
front of the fuselage to the base of the inner interplanc 
strut. 

Tin- tail skid, which is attached to a small fin uinl. r 
neath the fuselage, is const ructed of wood, and i termi- 
nated by four steel laminations ,M)< m. thick. 

The skid is sprung with elastic cord. 




The Ace-Motored Single Seater Ace Biplane 



The small light, economical single-seater ACE Biplane 
has been designed to answer certain requisites as follows: 

Its wing spread of only 28 ft. 4 in., overall length of 
1 8 ft., and 7 ft. height insure a very small and economical 
hangar for housing and workshop facilities. It is strictly 
a one-man machine, not only in flying but in being handled 
on the ground as well, as one man can pick up the tail and 
easily pull the machine into the hangar alone without aid 
of mechanic or extra help, because of its lightness. 

The performance of the ACE embodies the best assets 
of commercial aviation, such as a quick take-off, fast 
climb ( wide range of flying speed, slow flat glide with a 
twenty-five mile per hour landing speed and a very short 
roll which averages about sixty feet after the wheels touch 
the ground. 

To the above qualities are added the items of moderate 
cost and upkeep. The selling price being $'2,500 places 
the machine well within the reach of any pilot and the 
maintenance is one-third that of the average aeroplane. 
Gasoline consumption is under five gallons per hour and 
with a twelve gallon tank one has a cruising radius of two 
and one-half hours. 

High grade construction is the first requisite which 
proves itself in giving a factor of safety of over 8. An- 
other feature is the short space of time in which the 
machine can be assembled, due to the self-aligning fixed 
strut construction which eliminates the necessity and ex- 
pense of an expert aeroplane mechanic. 

The machine has been designed with the idea of it being 
used not alone as a single-seater sport plane but for com- 
mercial purposes as well; such as carrying mail, light ex- 
press, advertising, exhibition work, and to be used by 



204 



aerial police forces, etc. 

In recent test flights one hundred and eighty pounds 
of sand was carried in the spare space of the machine, in 
addition to a full load of fuel and the pilot. No notice- 
able depreciation in climbing was observed. This speaks 
well for the efficient design and proves that the machine 
can carry extra weight. 

The machine was tested out at the ACE Flying Field, 
Central Park, L. I., by the Company's test pilot, Bruce 
Eytinge, formerly a First Lieutenant Instructor and Test 
Pilot in the Royal Air Force for 18 months. On the first 
altitude test a height of 6000 feet was reached in 20 min- 
utes and later 8000 feet was reached in 28 minutes. Per- 
fect stability and height climb were observed at this alti- 
tude. On flying level the throttle was retarded 50 per 
cent, and the machine proceeded in straight horizontal 
flight flying level on half the motor's r.p.m.'s. When the 
throttle was entirely retarded idling the motor the ma- 
chine nosed down into a slow flat glide. 

Other tests of the machine's speed show that with full 
throttle it is capable of 65 m.p.h. In testing the gliding 
quality the pilot began a glide from an altitude of 8000 
feet over Mineula at a distance of about 8 miles from 
the flying field and continued in the glide past his field to 
Amity ville. a distance of about a 11 mile glide and then 
turned back to glide into the airdome. In this maneuver 
a time of 1 5 minutes elapsed before the ground was 
reached and a landing was made about 20 feet from the 
hangar with a dead motor. The above test shows that in 
case of a forced landing from an altitude of about 3000 
to 1000 feet the pilot will have ample time to select 
landing field within a radius of 10 miles. 



SI\(,I.K MOTOKKI) AEROPLANES 




The Ace in Hight and after dim bing to 8000 feet in M minutes 



Safety Factor 

Selected \\Ysteni spruce is used for all principal parU 
of wings, struts and fus< -lagc. etc. The complete whiff 
structure iiiuler a sand load test have supported in excess 
of ten times the weight carried in flying. Flying tests 
have shown a high factor of safety under difficult condi- 
tions of /.ooming. tail slide and whip stall, loops, spinning 
nose dive, inuncrinan turns and falling leaf. etc. The 
inai-liine is so designed that it has great inherent stability 
and if the controls are released when stunting the machine 
will right itself from any position. 

Assembling Facility 

One does not have to be an expert aeroplane mechanic 
to tinerate and assemble the ACK Biplane. This item is 
expediated by the employment of only two flying wires, 
two landing wires, two drift and two anti-drift wires, and 
two drift struts. The fixed stagger and angle of inci- 
dence are obtained through the employment of special 
single self-aligning struts. The lower planes have a 3 
dihedral angle while the upper planes are neutral. 

General Specifications 

Span, upper plane Jfl ft. 4 in. 

I-enjrth. overall 1H ft. 

I l.-i|rtit, overall 7 ft. 6 in. 

Wheel tread 60 in. 

\Vhtfl iliiunrter 36 in. 

Siie of tire i6 in. x 3 in. 

Controls 

Lateral and longitudinal balances are operated by stick 
ontrol. The rudder is ojx-rated by a foot bar. All con- 
Ilinir surfaces are large and balanced affording ease of 
itrol and the response is so immediate as to require but 
i slight movement of the control stick or rudder bar. All 
nntrol wires are assembled in duplicate seta. 

Fuselage 

The fuselage is of good streamline form. It is of War- 
ren-truss construction. The cockpit is of 3 ply veneer. 
I age is braced with piona wire from the pilot's 
kpit forward, and with T section struts diagonally stag- 
gered from the cockpit rearward, eliminating all wires and 
The motor and members bearing heavy stresses 



are attached to a substantial pressed steel nose plate. 
The motor is bolted directly to the plate, and by eliminat- 
ing engine beds every part of the motor is immediately 
MCeadbfe. This is the most rigid motor mounting ever 
furnished in any aeroplane ami the absence of vibration 
is a noticeable feature. The nose is covered with alumi- 
num, the hood being arranged in quick detachable sections 
giving easy access to the motor. The remainder is eo\ 
ered with linen, doped, colored and varnished. The body 
tapers to the rear on which the double cambered rudder is 
hinged. On the instrument Imard in the cockpit to the 
pilot's left is the ignition .switch and choke wire, to his 
right is the gasoline throttle and in the center an oil pres- 
sure gauge, radiator thermometer, a revolution counter 
and an altimeter to indicate height. 

Landing Gear 

The chassis is of the ordinary V type, each V con- 
structed from one piece one inch tubing. Elastic chord 
shock absorber binds the axle to the struts. An under- 
carried skid of hickory fastened to the center of the nxle 
and braced with two streamlined tubular struts prevents 
the nosing over and eliminates the ever present danger of 
damage from overturning. In landing the tail of the skid 
acts as a brake, bringing the machine to rest after a 
very short roll of about 6<) feet. This feature makes the 
machine the safest and most suitable for small fields. 

Tail Group 

The tail plane is a fixed stabiliser of single cambered 
surface to which is hinged the balanced elevator flaps. 
The vertical fin is a fixed stabiliser of double camber to 
which is hinged the balanced rudder. The large bal- 
anced controlling surfaces and the undercarriage skid 
make this machine the easiest and safest to taxi, as OIK 
can easily taxi in a straight line or make a turn in a very 
small space. 

Motor Group 

An ACE four cylinder sixteen valve head. 4O h.p., 
water-cooled motor is used. The motor has been so care- 
fully balanced as to entirely eliminate vibration. Its 
weight is 146 Ibs. The cooling system is Thcrmo-svphon 
with ample water capacity. A five foot pro|>cllcr is 



206 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A skeleton view of the "Ace," showing construction 



driven direct from the crank shaft at 2000 r.p.m. A 
spinner is used on the propeller over the hub and is so 
attached in front of the motor so as to form with the rest 
of the body a perfect streamline with low head resistance 
and giving a very neat appearance. The Atwater-Kent 
battery ignition system is used which affords ease in 



starting. Lubrication is full force feed by a spur ge; 
pump. Gasoline system is gravity feed from a 12-gallo 
tank in front of the pilot and separated from the mote 
by a fire wall. Zenith carburetor is used which afforc 
economic and efficient carburation. 




The I.oening Two-Sea 
er Monoplane, equippt 
with a :!00 h.p. Hispan 
Suiza engine. 







The Bristol Monoplane, equipped with a Le Rhone engine. This machine has a wing span of 30 ft. 9 in.; length over all -20 ft 

4 in.; chord 5 ft. 11 in.; wing area 145 ft. 



SIN(;i.K MOTOKK1) .\KHUIM..\\KS 




HANNOVFRANFR B1P 

5PAN 


LANE. 


96' Si- 
s' I0r 

y 
f r 

s <r 


L Jl] 

i 

g 


_^ 
1 


Lower Plane 
CHORD _ 
QAP - (about) 
TAI1.PLANE SPAN ... (Upperl 
... (Lower) 
OVERALL LENGTH 
ENGINE (Opel-Arpu) 
PROPELLER 
TRACK 


5* iX 
ISO H.P. 

9' 1" U 

f tr \ 




N^ 


/-] p Zix ^[ 


V . I 


"> 




^ 


/ 





The Hannoveraner Biplane 



M ncrallv s| akin;;, the construction is of wood through- 
lit, si,, 1 hcing U se,l sparingly, except in the intcrplanc 
truts. landing chassis struts, c. ntn- section and some de- 
iils of the tail. 

The construction throughout is sound, and the finish 
uit<- i;ood. 

Tin performance- of the ni.-iehine is good. 

The leading particulars of the plane arc as follows: 
Vci^ht. Kmpty. l.?:l.' |li>. 
nt.-d Weight. .',-.;.' His. 
rr.-i of Ipp.-r Winers. _>|7.(i si|. ft. 
ir.-.i ,if I.,, WIT Wiiijfs, H_>.J sq. ft. 
nl. -i I \re;i ul \Viri(rs, Hiid.o S (|. ft. 

ilin^ pi r s.| ft. of \Viti(t Surfnee, i.Jfl Ihs. 
irrn of Aileron, each. lli.J MJ. ft. 
irrii of Hiiliinee nf Ailrnin. l.fi M). ft. 
iren of Top Pl.un- or Tail, KM) si|. ft. 
n-;i of It, .11, MM Hum- of Tail, !!!..' s<|. ft. 
il Vr.Ni of Tail Plane, ...> s |. ft. 

i Kin, (i.j sq. ft. approx. 
rca of Kiiil.lrr. li.t sq. ft. 

f Kleuitors, J.'.o si|. ft. 
lori/ont.il \n-;i of |li H ly. .VJ..' sq. ft. 
<-rtii-;il \rra of Body. II I. li -n. ft. 
till \Veifrht prr h.p., H.U His. p ( -r h.p. 
re. Pilot mid Ohscrver. 

riii.Hiient. 1 Spanclnu Orin^ throiifrfi propeller. 1 Pcrnhellum 
mi rinjr mounting. 

fini-. (ipi-l \r^ns. I MI h.p. 

rtrol Capacity, :(7 > , jrallons. 

ity. :i Dillons. 

Performance 
) Climb to i,000 feet, 1 min-.. 

Rate of climb in ft. prr mln^ 490. 



ln<licat<-<l air sprrcl. 6. 

Hi-volutions of Kn^iiif, l.lfi;,. 
(I)) Climb to Kl.(HM) ft.. Is m ins. 

Hull- of climli in ft. p,-r min.. 340. 

Imlieati-il air spc<-<l, 64. 

Hrvoliitions of Kiipinc. 1. 17.1. 
(c) Climb to l:l.(HKl ft.. .><l mii,s.. f, 

Hate of dim)) in ft. p<- r min.. |!u. 

Indicated air speed, (i.>. 

Kcvolutions of Knjrinr. 1,444. 

Speed 

At 10,000 ft. 96 miles an hour; Revolutions, 1,464. 
At 13,000 89'/ z miles an hour; Revolutions. l.:,_><>. 
Service ceiling at which rate of climli is loo ft. p,- r mi,,., U.OOO. 
Kstimateil absolute ceilinfr, 16,400. 
Greatest heifrht reached, M.MHi in :t;i n,ii,s. in sees. 
Hate of climb at Ibis beipht, IJO ft. per mill. 
Air endurance, nlnnit .'_. hours nt full sprrl at |(i,(HK) ft., j n . 

cludiii); climb to this height. 
Military load. 444 Iba. 

The machine is nose-heavy with the engine off. and 
slightly tail-heavy with the engine on. It tends to turn 
to the left with the engine on. 

The machine is generally light on controls, except that 
the elevator seems rather insufficient at slow sp.-cds. It 
ia not very tiring to fly. and pulls up very (juicklv on 
landing. 

The view is particularly good for hoth pilot and oli 
server. The former sit.s with his eyes on a level with the 
top plane, and also enjoys a good view below him on 
account of the narrow chord of the lower plane. 



208 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Rumpler Two-seater Biplane with 160 h.p. Mercedes engine 

Halberstadt 160 Mercedes 



It was reported that the center thrust and the center 
of resistance of the plane were too far apart, so that there 
was a tendency to stall with the engine on, and to dive 
with the engine off. Directionally, owing to propeller 
torque, the machine would swing to the left, but, with 
engine off, would be neutral. 

Controllability and manceuverability were good. 

Details of Weight and Load Carried 
Weight 

Average total weight of machine fully loaded 4,220 Ins. 

Load Carried 

Pilot 18 lhs - 

Observer 18 lhs - 

Vickers gun 

Lewis gun 

Deadweight 



Standard 
Height 
10,000 
13,000 
15,000 
16,000 



Speed 
M.p.h. 
117.5 
113.5 
110.5 
108.5 



Speeds at Heights 

R.p.m. 
1,590 
1,565 
1,545 
1,530 



Speed 
M.p.h. 
120.5 
116.5 
114 
112 



R.p.m. 

1,725 
1,700 
1,675 
1,665 



16 Ibs. 
134 Ibs. 



Total load 545 lbs - 

Carburetor, Zenith, 2,004, 2,394; jets, 289 main, 340 compensator. 

Climbs 

Result of Trials 

A. B. 8,781 X. 3,012m. 

R. of C. 
ft./min. R.p.m. A.s.i. 

(1,540) 

1,040 1,620 71 
875 1,615 70 
600 1,605 69 
330 1,580 67 
275 1,575 66 



StandardTime 


H.ofC 


Time 


Height Mins. ft./min. 


R.p.m. A. 


s.i. Mins. 










(1,365) 







2,000 


2.0 


935 


1,460 


71 


1.8 


5,000 


5.6 


770 


1,460 


70 


5.0 


10,000 


13.5 


500 


1,450 


69 


11.8 


15,000 


27.8 


230 


1,430 


67 


22.9 


16,000 


32.75 


180 


1,425 


66 


26.2 



Trials at 4,500 ft. Giving Relation between Speed and Revolu- 
tions per Minute Flying Level 



Flow 
Gals./Hr. 

25 

81% 

17 

14% 

12 
10% 
9 



The installation of the 160 h.p. Mercedes is on the 
usual German lines with center section radiator, main 
pressure tank, and gravity tank in top center section. 

The wing structure is a single bay design with the bay 
longer than usual in proportion to the gap. There is a 
small anhedral angle on the top planes, and dihedral on 
the bottom. The center section is covered top and bottom 
with plywood. 

The fuselage is three-ply, covered and tapers to a hori- 



Speed 




Flow 


Speed 




M.p.h. 


R.p.m. 


Gals./Hr. 


M.p.h. 


R.p.m. 


124 


1,600 


24 


127 


1,760 


120 


1,560 


21 


120 


1,685 


11C 


1,470 


17y 4 


110 


1,575 


100 


1,375 


14'/2 


100 


1,470 


90 


1,280 


12y 2 


90 


1,365 


80 


1,185 


10% 


80 


1,260 


70 


1,085 


V4 


70 


1,150 



SINCLK MOTOKK1) AKUOl'l.AN K.s 



209 




i- nf tin- |MK!V of the Hallterstiidt two-seater biplane, 160 h.p. Mercedes engine. The Inset is a sketch of the tall plain-* 



zontnl inrinlirr. the width remaining constant. This al- 
lows the ri_-iil fixing for the tail plane, no bracing or 
struts being needed. 

The tail plane is adjustable on the ground only. Tin- 
pilot's and gunner's cockpit are constructed as one, with- 
out apparently weakening the fuselage. 

II I' at revolutions not known. 

Propeller Dia. 274 cm. Pitch, 900 cm. (marked). 

2,747 mm. 3,095 mm. (measured). 

Military load 545 Ib*. 
Total weight, fully loaded 2,539 Ihs. 
W.-iirht ,>,T M). ft. 8.2 Ib*. 
\\ '. ijrht pr h.p. 15.83 Ibs. (h.p. assumed 160). 



M.p.h. H.p.m. 

S|-cd at 13,000 ft 8* 135J approx. 

S|.-<l at 10,000 ft 97 1,'W5 approx. 



Mln. Sec. 

Climb to 5,000 ft 9 25 

Climl. to 10,000 ft 24 30 

Climb to 14,000 ft 51 55 



R.ofC. in 
ft. per mln. 

240 

240 
80 



4 

64 



Service ceiling (height at which rate of climb Is 100 ft. per mln.) 

13.500 ft. 

Kstinintrcl nl.solute cellln(r 16,000 ft. 
Greatest heiirfit reached 14^00 ft. in 64 min. 40 sees. Rate of 

climb at this height 50 ft. per min. 



210 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Front view of Pfiilz single-seated (ifrht- 
iii).' plane, equipped with 1KO h.p. -Mer- 
ivdes engine 



The principal dimensions of the Pfalz D.III. are as 
follows : 

Span of upper wing 9M metres. 

Span of lower wing 7.80 

Total length 7.06 

Height -'.67 

Wings 

The planes are unequal in span and chord, and stag- 
gered greatly forward, namely 0.43 metres. The planes 
are not swept-back. The lower planes have a slight di- 
hedral angle. The trailing edges of the wings are rigid. 

The upper plane is trapezoidal in form, with rounded 
corners. The trailing edge is cut away in the centre, the 
recess being shallow from back to front (0.225 metres) 
but very wide (1.65 metres). 

At the ends of the upper plane are balanced ailerons. 
The plane is constructed in one piece, and the chord is 
uniformly 1.65 metres. Along the whole length are 12 
ribs made of wood, and spaced 0.84 metres from one an- 
other. The incidence of the seventh rib is 3% degrees. 
Between each pair of ribs are three strips of wood 
strengthening the leading edge, the middle of these runs 
back to the rear spar, while the two others, which are 
very small, stop at the front spar. 

The two main spars are built of spruce. They are 
hollow rectangular boxes. The front spar is 0.20 metres 
from the leading edge, and the rear spar 0.65 metres from 
the trailing edge. It follows, therefore, that the distance 
between the axes of the spars is 0.80 metres. The posi- 
tion is maintained by four interposed steel tubes. The 
structure is internally braced by crossed piano wires. 

In the thickness of the centre section of the wings is 
found a petrol tank on the left, and the radiator on the 
right. This section is heavily reinforced with plywood. 

The ailerons are balanced and upturned, and their chord 
is 0.4 metres at the h'-nge, and 0.73 metres at the broad- 
est part of the balanced portion. They are 2.265 metres 
long. 

Control is transmitted from the control pillar to the lev- 
ers of the ailerons by 3 mm. cables passing through the 
interior of the lower wings. 

The lower planes are trapezoidal in form, as are the 
upper planes, and the ends are very rounded and upturned. 
Their chord is 1.2 metres. 

At a point 0.2 metres from the leading edge is found 
the front main spar, the rear spar is 0.5 metres from the 



The Pfalz Biplane D. III. 

trailing edge, and the distance between the spars from 
axis to axis is 0.5 metres, as compared with that of 0.8 
metres in the upper plane. The difference in this dis- 
tance is caused by the difference in the chords of the 
wings. 

On each wing are 10 wooden ribs, spaced 0.35 metres 
apart. At the seventh rib, that is to say, near the base of 
the interplane strut, the incidence is 3 deg. 

At 12 cm. from the extremity of the first rib on the 
lower left-hand wing is a strip of stamped metal, 24 cm. 
wide, resting on the two main spars and forming a foot- 
board. 

The system of false ribs and compression tubes is the 
same as that in the upper plane. 

The lower planes are attached to shoulders constructed 
on the lower walls of the fuselage. 

The gap between the planes is 1.415 metres in line with 
the fuselage, and 1.375 metres at the base of the inter- 
plane struts, so the dihedral is not very apparent. 

The cabane slopes outwards and upwards. 

The struts of the cabane, and those between the planes, 
are very large and thick, and are formed of streamline 
timber. They are of a U-shape, arranged upside down 
in the cabane struts, and the right way up in the plane 
struts, the cross-pieces, which unite the legs of the U in 
the cabane struts, being found above, whereas those which 
unite the legs of the interplane struts are below. 

All these struts are fixed with the aid of cup-joints, 
and carry sheet metal ferrules at their four poii.ts of at- 
tachment. 

Viewed from the front the interplane struts are in- 
clined outwards, the distance between the tops of the in- 
terplane struts being 0.318 metres greater along the planes 
than their bases. The distance between their front and 
rear branches corresponds to the distance between the 
main spars in the upper plane, to which they are attached. 
Their attachment to the lower planes is different, and is 
made to the piece of timber which unites the two main 
spars. 

These two lower points of attachment are 0.3 metres 
apart from axis to axis. 

Bracing. The plane-bracing is attached to the sides 
of the fuselage. 

Two 4 mm. cables run from the summit of the cabane 
to the shoulders on the lower part of the fuselage. 

Two 4 mm. cables run from the top and bottom re- 
spectively of the front interplane strut, one to the front 



SIXCI.K MOTOHKl) .\KH01M..\\KS 



111 



xirw nf tin- I'fil/ -vi 
plane 



-eileil 




Iff of the undcr-earriagc, and the other to the summit 

of thr front cahanc strut. 

'J'wn ntlirr t nun. cables run from tin- top and bottom 
rcsp! cthely of (In- rear intcrplanc strut, the first to the 
front of thr slioulilrr of tin- I'IIM laire. tin- second to the 
.summit of the 1 rear cabane strut. These cables have a 
inel il i-o -i-lion it their intersection. 

A Mi|i|ili meut.-iry i-ablr. .: nun. ili.-imcter, completes the 
.structure of tin- iiii;s. .-ind roiinrrts the base of the intcr- 
plane struts to the end of the upper plane. Its point of 
att.-irhuii nt is found outside these struts, 0.81 metres 
from tin summit. 

All thrse eahles are connected to lugs fixed on the spars, 
and ire independent of the interplanc struts. 

The Tail 

Tli> ti\. ,| tail-plane is trapezoidal with a rounded Icad- 
:_' to its front part. Its greatest depth is 0.88 
metres, its width is .' l : m.tres. A permanent portion 
of plvui><j is limit into the fuselage, to which is an- 
chored the fixed tail-plane proper. The assemblage and 
fi\iiiL r of tin se sections is achieved by two bands of metal 
placed it their junction aboM- and I.elou. and bolted in 
pli<< One dm s not remark the cable found in the first 
moil.ls brought down. 

Tlie elevator, which is unbalanced, is formed of a sin- 
gle flap, constructed of steel tube covered with fabric. 
Its ilimeiisions are 0.452 metres chord by 2.65 metres 
span. 

Tin- rudder is balanced, and has the appearance of an 
oval inclined towards the rear. It is situated entirely 
;il.,,', , tin- elevators. Its structure is metallic. 

Tin- fixed fin, of trapezoidal shape, is formed of ply- 
wood, and is moulded bodily into the fuselage. The con- 
trols are worked by 3 mm. cables, which pass through the 
interior of the fuselage, and do not come out until they 
arc within one metre of its rear extremity. 

The Fuselage 

fuselage of the Pfalz I). III. is of monocoque type, 
oval in section, and it tapers vertically towards the tail. 
Its seetion is very large at the portion between the 
lmt \rry narrow in front and towards the renr, 
presenting a remarkable likeness to a torpedo. 

It is entirely constructed of bands of plywood, 9 em. 
wide, and it terminates on the upper side with ridge. 



It is apparently constructed in two halves on moulds (like 
the early Deperdussins of Mr. Koolhov. us design), after 
which the whole structure is covered with thin fabric and 
painted. 

Inside the fuselage are found eight very thin cross par- 
titions, which divide up its whole length. There are also 
eight small longerons; one in the ridge along the back, 
(lire,- on cither side, and one at the \> 

The section at the centre of gravity is 0.865 x 1.16 m. 
taken at the axis of the lower plane. 

Controls 

The control of the machine is effected with the aid of 
a control column with a handle formed of two branches 
sloping towards the pilot. The hand-grips are bound 
with cord. In the centre are two buttons which work 
the machine-guns. Thr control column can be fixed when 
climbing or diving by n little toothed wheel. 

The rudder bar is adjustable and the seat is fixed. 

Tin- starting magneto is found on the left-hand side 
in front of the pilot. 

Level with the pilot under the fuselage are two holes 
with plugs, to permit the draining off of oil. petrol, or 
water, which might damage the plywood if allowed to 
collect. 

.lust in front of the tail-plane there is found, on either 
side of the fuselage, an opening large enough for the 
passage of the hand. This gives a better grip when lift- 
ing the machine than would the bare fuselage. 

The tail-skid of special section is constructed of ash, 
and is reinforced by metal where it touches the ground. 
The springing of the tail-skid is effected by elastic cord. 

The airscrew in common use is an " Axial " 2.82 metres 
in diameter, placed underneath a revolving pot, or " cas- 
serole." On certain other Pfalz aeroplanes has been 
found the " Heine " airscrew, 2.78 metres in diameter, or 
yet again the " Imperial " airscrew 2.70 metres diam< r 

The Engine 

The engine is a modified I60-!i.p. Mercedes, c<|iiippcd 
with double ignition, and a horizontal exhaust pi|>c on 
the right-hand side. The form of the exhaust pipe \ m- s 
In certain types it is a cornucopia, and the emission nf 
gas l made in front of the first cylinder. On other ma- 
chines the end of the exhaust pipe is taken in the reverse 
direction, the exhaust being emitted, instead, at the rear 
of the last cylinder. 



212 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



The engine cowl leaves the upper part of the cylinders 
uncovered. 

The petrol supply is provided by a main tank of about 
70 litres capacity, placed in front of the pilot on the floor 
of the machine, and by a tank built into the upper plane 
with a capacity of -10 litres. In all, 110 litres of petrol 
are carried and 15 litres of oil. 

The radiator is of the system of layers frequently em- 
ployed in chasing machines. It contains 40 litres of wa- 
ter. On its lower face is found a large aluminium plate 
fixed in two grooves, which makes it possible for the pilot 
to cover or uncover the radiating surface. 

Armament. This consists of two fixed Spandau ma- 
chine-guns operated by the engine, and firing through the 
airscrew. They are arranged one on each side, a little 
above the cylinders, and can be fired separately or to- 
gether. 

The Landing Carriage. This is formed by four 



streamline steel tubes 50 by 30 mm., which constitute two 
"Vs." 

The two front legs are joined by an arched strip of 
metal which supports the front portion of the fuselage. 
A lug embodied in the upper extremity of eacli strut forms 
the attachment of a cable running to the front interplane 
strut. 

The steel axle, 53 mm. diameter, is placed between two 
wooden pieces. A movable and hinged plate covers the 
whole arrangement, and acts as a streamline fairing. The 
suspension is rendered elastic with the aid of metal springs 
covered with fabric, arranged like rubber cord. 

A metal cable limits the travel of the axle. 

The track of the wheels is 1.72 metres. The wheels 
are fitted with 760 by 100 mm. tires. 

Below is given a summary of results on tests of several 
German aeroplanes : 




View from above of the German Pfalz single-seater fighter, showing rudder construction. 



SINC.I.K MOTOKK1) A KHO1M ,.\ \ | g 



Vr- 




'214 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 
Pfalz Scout 828 4 17 160 Mercedes 



The performance of this machine appears to be prac- 
tically the same as that of G/141 Pfalz Scout with 160 
h.p. Mercedes, tested in March, 1918. 
Summary of Results 



gib 


u 

Q 


d .5 


5 




._: 


1.5 


= 
o< 


5 
p. 


1 


jj 




BS 4) 


d 




j 


H ^ 


PS ^ 


pa 


< 





(1,335) 


(1,320) 




5,000 


7.0 


606 


1,370 




67 


6.9 


605 


1,330 


73 


10,000 


17.3 


373 


1,350 




61 


17.5 


360 


1,310 


57 


14,000 32.3 


187 


1,320 


54 


33.7 


160 


1,290 


61 


Standard 
Height 
10,000 




Speed 
M.p.h. 
98.0 


R.p.m. 
1,415 


Speed 
M.p.h. 
102.5 


R.p.m. 

1,400 


13,000 




94.8 


1,395 


96.0 


1,355 



Details of Weight and Load Carried 

8,284/17 G/141 

Military Load 3l ". 281 Ibs. 

Total Weight, fully loaded 2,085 Ibs. 2,056 Ibs. 

On this machine lift wires have been added to the over- 
hang, running from bottom rear main plane fitting to 
about half way along the back spar overhang. 

Front openings have been cut in the engine cowling to 
the cylinders, the former Pfalz being left plain. 

The tail plane has been increased from 12.1 sq. ft. to 
16.2 sq. ft., but the shape has been altered, being now 
nearly semi-circular. 

Main plane incidence and tail plane setting are approxi- 
mately the same. 



Trials on Aviatik No. G.H.Q./4 



Duty Reconnaissance. 

Engine Benz. Assumed 200 h.p. 

Propeller Wotan. Dia. 3,004. Pitch 1,650 (measured). 

Military load 545 Ibs. 

Total weight fully loaded 3,325 Ibs. 

Weight per sq. ft. 7.46 Ibs. 

Weight per h.p. 16.62 Ibs. 

M.p.h. Revs. 

Speed at 10,000 ft 9?i/ 2 MOO 

Speed at 15,000 ft 89'/ 2 1,510 





R.ofC. 


Indicated 




Min. Sec. 


ft./min. 


Air Speed 


Revs. 


19 45 


345 


63 


1,490 


40 15 


165 


58 


1,470 



Climb to 10,000 ft.... 
Climb to 15,000 ft.... 
Service ceiling (height at which rate of climb is 100 ft. per mm.) 

16,750 ft. 

Estimated absolute ceiling 19,500 ft. 
Greatest height reached 1 7,000 ft., in 5(i min. 20 sec. 
Rate of climb at this height 90 ft. per min. 



Dimensions and Equipment of the 1918-1919 Types of German Aeroplanes 

The following table permits readers to compare the points of the fighting German aeroplanes : 



Machine 



Type 



Albatros D. II 

Albatros D. Ill 

Torpedo D 

Roland D- II 

Halberstadt D 

Fokker 

Rex D- II 

Roland C 

A. E. G C. IV 

L. V. G C. IV 

D. F. W. Aviatik C. V 

Albatros B. F. W. . . . C. V 

Rumpler 

Gotha G. I. 

A. E. G 



' r 
' 1i 

5* 


Span 
Upper Lower 

ft. in. ft. in. 

07 s OR 1 


Gap 

ft. in. 
4 


Chord 

ft. in. 
5 3 


Length 
Over All Motor 

ft. in. 

24 O MprppHps 


"3 

1! 

175 


s . 

E 

2 


6 
C 





"9 


g 


28 


g 


4 


10 


4 10 


24 





Mercedes 


175 


2 

























Mercedes 


175 


2 







29 


g 


28 


o 


4 


4 


4 9 


22 


fi 




175 


2 







28 


6 


25 


9 


4 


3 


4 10 


24 





Mercedes or Argus . . . 


120 


2 







29 


6 


20 


6 


4 


3 


4 10 


24 





Mercedes or Oberursel 


175 


9 







33 





33 





4 


o 


5 3 








175 


1 




a 


42 


g 


41 





g 


a 


5 5 


23 


g 




175 


2 


4 


n 


44 


g 










6 5 


28 







235 


2 


4 


-i 


43 


g 


42 


o 


5 


g 


5 9 








228 


2 


6 


a 


41 


3 


40 


o 


5 


10 


5 10 


28 


o 




225 


a 


4 


a 




















Mercedes 


260 


2 


6 


g 


78 





79 





7 


a 


7 g 


41 


o 




520 


3 


14 


3 




















Two Benz . 


450 


2 





.. 

''' 

A tf 

(/ \ I/ 






GERMAN 'TYPE. C IV 

&UMPLEQ 

Z60 HP I9IT MPLANE 



Jcale of feet 

I^^^T"~I M I T I T T I 

*> i * 'Q " 



Mclaughlin 



215 



216 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The German Rumpler Biplane 

The C. IV Rumpler Biplane 



The Rumpler biplane described below is a general util- 
ity machine, and is perhaps the best in its class. It is 
chiefly of interest on account of its great speed, which is 
equal to that of a chaser single-seater, and also on ac- 
count of its high "ceiling" (6.500 metres). The climb 
of the Rumpler C.IV is also very good (5000 metres in 
35 minutes). 

General Specifications 

Span, upper plane 12.60 Metres 

Span, lower plane 12.10 . Metres 

Chord, upper plane 1.70 Metres 

Chord, lower plane 1.30 Metres 

Area, upper plane 20 Sq. Metres 

Area, lower plane 13.50 Sq. Metres 

Gap between planes 1.85 Metres 

Stagger 0.60 Metres 

Overall length 8.40 Metres 

Overall height 3.25 Metres 

Engine, Mercedes 260 h.p. 

or Mayhach 250 h.p. 

Climb in 35 minutes 5,000 Metres 

Wings 

Both upper and lower wings are swept back 3 degrees. 
There is a dihedral angle of 2 degrees and the wings are 
staggered forward 0.60 metres. The trailing edge, con- 
trary to usual German practice, is rigid. The ribs, which 
are made of three-ply wood, pierced for lightness, are 
spaced 0.30 metres apart. Their angle of incidence is 
uniform and is equal to 5 degrees. 

In the plan the upper wings are of trapezoidal form, 
with rounded angles. Above the fuselage the trailing edge 
is cut out as shown in the illustrations. The maximum 
chord is 1.70 m. In each of the upper wings there are 
19 main ribs, and five compression struts of steel tubes. 
The ailerons are of the tapering type, their chord vary- 
ing from 0.50 to 0.65 m. The lower wings, as in so many 
other German machines, have rounded wing tips. As the 
radius of the arc forming the rear edge is longer than 
that of the front, the wing tip somewhat resembles that 



of a propeller blade. Each of the lower wings has 17 
main ribs, and four steel tube compression struts. 

The interplane struts, of which there are two pairs on 
each side of the fuselage, are oblique. In section, the 
inner front struts measure 0.105 m., and the rear strut 
0.130 m., while the outer front strut measures 0.090 m. 
and the rear outer strut 0.085 m. The gap between the 
wings is 1.85 m., and the total lifting surface is .S3. 5 
square metres, of which the upper wing is 20 square me- 
tres and the lower wing 13.5. 

Tail 

The tail plane, which is not adjustable, is not so deep 
as in previous types. In plan, the leading edge of the 
tail plane is approximately a semi-circle. This tail plane 
is supported on each side by struts attached at their other 
end to the bottom rail of the fuselage. Two other struts 
brace the tail plane to the vertical fin. The struts under 
the tail plane are provided with a series of sharp-edged 
metal points. It appears probable that the object of 
these is to prevent the landing crew, when wheeling the 
machine about, from catching hold of these struts, thus 
possibly bending them. The elevator is in two parts, each 
of which is partly balanced by a triangular forward pro- 
jection. The rudder, which is built up of metal tubes, is 
of the usual type, and the control cables pass inside the 
fuselage, guided at points through small wooden tubes. 

Fuselage 

The construction of the fuselage is of the current type, 
with four longerons and struts and cross members, braced 
by piano wire. Front and rear are covered with three- 
ply wood, and the middle with fabric. The propeller (ai 
Heine) has a diameter of 3.17 m. As on all other Ger- 
man machines, the propeller boss is enclosed in a " spin- 
ner." 

Engine 

The motor fitted on the Rumpler is either a 260 h.p. 



SINC;i.K MOTOKK1) A KK( >1'1 . \ \ I - 



-.'IT 




\ liMMipl.-r type of German machine. Vote the lo.v.ti,.i. ..f the radiators 



Mcrrr.lrs or a -'.-><> h.p. Maybach. both having six v. r 
tical cylinders. 

When Hi. Mere,-,!.-, i, titt.-d, it is slightly tilted to the 
right, in order to allow thr induction pipes to pass between 
tin- legs of thr cabanr. With tin- May bach, which offers 
less riiriinihr.-inrr. this arrangement is not necessary. The 
motor is supplied with furl fnnn two tanks. The main 
,,n, (about -."Jd litrrs) is placed under tlir scat of tin- 
pilot, thr second, the serviee tank (about 70 litres), is 
pla, -,,! ,t the back of thr pilot between him and the gun 
rim: in thr Dinner's ,-oekpit. The quantity of fuel car- 
rird allows of a flight of four hours' duration. The eov- 
ering over Hi. mgine leaves the top of the cylinders ex- 
posed, .-.n.l encloses a Spandau machine gun operated by 
tin- motor. 

The exhaust pipes run from the six cylinders to a cor 
mon chimney, eurving upwards and backwards. The 
cliiiiinev itself is ,liided. about half way up, into three 
l.ranehrs. probably in order to obtain a certain amount 



of silencing effect. As in previous mod. Is. the radiator, 
which is semi-circular in shape, is placed on thr front 
,-f the eahane. In front of it is a series of small 
slats, whirh can hr moved so as to be either parallel to 
or at right angles to the direction of flight. This is, of 
course, don, in order to make it possible for the pilot to 
adjust the cooling according to the altitude at which he 

is Hying. 

Behind the motor is the pilot's cockpit, and behind 
again that of the gunner. Supported on a gun ring in the 
rear cockpit is a Parabellum machine-gun. Pilot and gun- 
ner are very close together. In the gunner's cockpit there 
is a bomb rack of the usual type, carrying four bombs. 
An opening in the floor permits of taking photographs, 
and the machine carries a wireless set. Thr landing 
chassis is of the V type, with rubber shock absorber.. 
There is no brake fitted on this machine. An external 
drift cahlr runs from the nose of the fuselage to the foot 
of thr inner front interplane strut. 




rrman Rumpler type machine 






CURTI5S 18-1 

400 HP 'K-12 ENGINE 

TRIPLANE 



Scale of Peet 



McUugtilij 



218 



SIM.I.K MOTOKK1) A KHO1M ,.\ \ I - 



The Curtiss 
Model 18-T Triplane 




This machine was designed for speed and great climb- 
ing ability. 

General Dimensions 

Wing Span I'pper Plane 31 ft. 11 in. 

Wing Span .Middle Plane 31 ft. n in. 

Wing Span Lower Plane 31 ft. \\ fa 

Depth of Wing ford (I'pper, Middle and Lower) 44 in. 
Gap iM-tween Wing- (In-twccn I'pper and 

Middle) 43 in. 

Cap iMtweeii Wing- (between Middle and 

Lower) 3*^ in. 

r None 

Length of Machine overall 93 ft. 3^ 8 in. 

Height of Machine overall 9 ft 10% in. 

Angle of Incidence gy t degrees 

Dihedral \ngle None 

;>l>ack 5 degrees 

Wing Curve Slonnc 

'iilal Stabiliser Angle of Incidence 0.5 degrees 

Areas 

Wings-- I'ppcr .' 119.0 sq. ft. 

Wing-- Middle 87.71 sq. ft. 

Wing- Lower 87.71 sq. ft. 

-on- (Middle 10.79; Lower 10.79) SIM sq. ft. 

llori/.ontal Slahilicer 14.3 sq. ft 

Vertical Stiibiliser 5.;.' sq. ft. 

..rs (each 6.51 ) 13.09 sq. ft 

Hiiddcr 8.66 sq. ft. 

Total supporting surface 309.0 sq. ft. 

Loading (weight carried per sq. ft. of support- 9.4 Ibs. 

ing surface) 

Loading (per r.h.p.) 7.35 Ibs. 

Weights 

Weight Machine Empty 1,895 Ihs. 

u eight Machine and Load 9,901 Ibs. 

f-efiil I ..ad 1.076 Ibs. 



Fuel 400 Ib*. 

Oil , 45 Ibg. 

Pilot and Pits.eiurer S30 Ibs. 

Useful load au\ |bs. 



Total 1.076 Ibs. 

Performance 

Speed Maximum Horisontal Flight 163 m.p.h. 
Speed Minimum Horisontal Flight 58 m.pji. 
Climbing Speed 15,000 ft. in 10 minute* 

Motor 
Model K-1J18-C) Under, Vee Four-Stroke Cycle. Water 

cooled. 

Horse Power (Rated) at 9,500 r.p.m. 400 

Weight per rated Horse Power I To 

Bore and Stroke 4% x 8 

Fuel Consumption per hour 36.7 gals. 

I in I Tank Capacity 67 gaU. 

( >il Capacity Provided Crankca-c 6 gauu 

Fuel Consumption per Brake Horse Power per .55 Ibs. 

hour 030 Ibs. 

Oil Consumption per Brake Horse Power per hour Wood 
Material Cl.ickitc 

Propeller 

Pitch according to requirements of performance. 
Diameter according to requirements of performance. 
Direction of notation (viewed from pilot's seat)... 

Details 

One pressure and one gravity gasoline tank located In fuselage. 
Tail skid independent of tail post; Landing gear wheel, sixe X 
In. x * in. 



Maximum Range 
At economical speed, about 55O mile-. 




Three-quarter rear rtew of the Curtiss Model 18-T Triplane with a 400 Kp. Curtiss Model K engine 



220 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 












SINC1.K MOTOKK1) AKKOIM.A NKS 



-'_' I 



ThriT ijiiarlrr re.-ir \ lew nf the Sopwilh 
TripL-inc. Vote tin- single struts and the 
uilrnms mi nil Hirer .: 




The Sopwith Triplane 



What prnli.ilily has led to the return of the triplane 
form of construction is tin- small span which it en- 
.ililt s n, to use. Another advantage of the triplane 
arraiigi nn nt is that tlif aspect r.-itio, which .should not he 
less tli.-in il. hut which in many machines of sii.irt span 
often has to It- considerably less, can be more easily ar- 
ranged for in the triplane. Thus in the case of the Sop- 
with triplane the chord is only little over 1 metre, and 
the span is 8 metres. The increased wing resistance is 
counteracted by the employment of only one strut on each 
.side anil a very simple wing bracing. Furthermore it is 
possible, owing to the light loading of the wing*, to con- 
struct the wing spars considerably lighter, and still have 
a comparatively great free length of spar, in the case of 
~ MM ith triplnnes about 2.75 m. with an overhang of 
l.Ni in. Tin- weight of the total wing area will there- 
fore sc.-ircely come out greater than in the case of a bi- 
plane of the same area. Possibly also the arrangement 
of the wings is advantageous as regards the view obtained 
by tli>- pilot, as the middle wing is about on a level with 
nd the upper and lower wings, on account of 
tin ir small chord, do not obstruct the view to as great 
an extent as the wings of the ordinary smaller biplane 
liavini: i greater wing chord. While both lift wires pass 
in front of the middle wing, the landing wire runs through 
it. The bracing cables for the body struts are crossed 
in the ease of those running forward to the nose of the 
machine, while those bracing the struts in a rearward 
>n are straight. The gap between the wings is 
!>n centimetres, and the stagger is about 25 per cent. All 
ngs are fitted with wing flaps connected by a ver- 
ei-1 band. In the nose the body carries a 110 h.p. 
t rotary motor, enclosed in a circular cowl, which 
s below the body in order to allow the air to escape. 
Tin- body is of rectangular section, rounded off in front 
by M ans of a light wooden framework in order to make 
it merge into the curve of the engine cowl. The width 
of the fuselage is 0.70 m., and it tapers to a vertical knife- 
edge at the back, to which the rudder is hinged. The 
elevator is in two parts, and has in front of it a tail plane 
of about 3 metre span, which, as in all Sopwith machines, 
can have its angle of incidence adjusted during flight. 

The area of the Sopwith triplane is 27 square metres, 
so that for a total weight of 670 kilogs. the wing loading 



is only 2. r > kilogs. per square metre. With such a light 
loading the machine has undoubtedly a considerable speed 
and a very good climb. Further particulars relating to 
these have not yet U -en published up to the present. The 
triplane is built both as a single-seater and as a two- 
seater, and has always a fixed machine-gun in front above 
the fuselage, and in the ease of the two-seater another 
machine-gun operated by the observer. This increase* 
the weight of the two-seater by about KM) kilogs. 

The under-carriagr consists, as in all Sopwith machines, 
of two V's of steel tubing and a divided wheel axle. Un- 
hinge of which is braced from the fuselage. 

The following remarks are taken from a technical re- 
port: 

The fuselage with tail plane and rudder is the same as 
that of the small Sopwith single-seater biplanes. The 
three wings have a span of 8.07 m. and a chord of 1 m. 
The lower and middle wings are attached to short wing 
sections on the fuselage. The upper plane is mounted on 
a small center section supported by struts from tin- body. 
Both spars of the upper wing are left solid, while those 
of the lower and middle are of I-section. The interplane 
struts, which are of spruce, and of streamline section. 
run from the upper to the lower wing, and the inner ones 
from the upper wing to the bottom rail of the fuselage. 
In order to give a better view the middle wing, which is 
on a level with the pilot's eyes, in cut away near the fuse- 
lage. 

The wing bracing is in the form of streamline wires 
of '/4"' n - diameter. The very simply arranged landing 
wires are in the plane of the struts, while the bracing of 
the body struts, as well as the duplicate lift wires, are 
taken further forward. From the rear spar of the mid- 
dle wing, wires are run forward and rearward to the up- 
per rail of the fuselage, and the lower wing also has a 
wire running forward to the lower rail of the body. All 
the planes have wing flaps, and inspection windows of 
celluloid are fitted over the pulleys for the wing flap 
cables. 

The motor is a 110 h.p. Clerget, and the petrol is led 
to the engine by means of a small propeller air pump 
mounted on the right hand lody strut. As the air screw 
was not in place we cannot give details of it. In tin- 
pilot's seat were the following instruments: On the right 



222 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A British pilot preparing for a flight in a Clerget-motored 
Sopwith triplane 

hand wheel for varying the angle of incidence of the tail 
planes, a hand operated air pump and a petrol indicator. 
In the middle, air speed indicator, manometer, clock, revs, 
indicator, and switch. On the left a petrol tap, lever for 



regulating the air, and lever for regulating the petrol. 
The weight of the machine empty was found to be 490 
kilogs., and if the useful load is assumed to be 200 kilogs., 
we obtain a total weight of 690 kilogs., which, with an 
area of 21.96 sq. metres, would give a loading of 31.4 
kilogs. per square metre. 

Further, the following particulars are given: Motor: 
Clerget, nominal h.p. 110, brake h.p. 118; fuel capacity 
for two hours, petrol 85 litres, oil 23 litres; area of wings 
and flaps (square metres), upper 7.90, middle 6.96, lower 
7.10, total 21.96; area of elevators 6 by .5, of wing flaps 
1.10, of rudder .41. Angle of incidence (degrees) : upper 
wing, root -(-I, tip .8; middle root -f- 1.5, tip -)- 1.5; 
lower, root -)-.5, tip .5 ; tail plane, variable -{- 2 to 
2 degrees. Loading per sq. metre, empty 22.3, fully 
loaded 31.4; loading per brake h.p. empty 4.15, fully 
loaded 5.85. 



At economic speed, about 550 miles. 



Fuselage with under-carriage and accessories .... 

Wings -. 

Tail plane, rudder and elevator 

Engine 

Petrol tank 

Oil tank 

Propeller 

Engine accessories 

Mounting 



Total weight empty 

Pilot 

Gun and ammunition 

85 litres of petrol and 23 litres of oil 



Weights 
in kilograms 
133.5 
135 
13 
160 
15 
8.5 
10 
16 
3 



Total weight, useful load 



490 
80 
40 
80 

-'00 




Interior of the Sopwith factory, showing one of the triplanes being assembled, and in the background the biplanes 



MULTI-MOTORED AKKoi'l.AM.s 



228 




The remarkable " baby " Caoroni triplane scout, the smallest member of the Caproni family, Mr. Capronl standing by 




Sim-,- UK- War, both the Cnpronl biplane and trlplanr have been remodelled for paswnp-r travel or rommerrial purposes. 
__ !.,,,! ,,,. I,..., lH-,-n litti-d with H rabin to accommodate eight JMTV.M-: outside there arc seat* for the two pilots and for nn..tbrr 
rnn-hnnic; iimlrr thr p.isM-nger seat* then- U riM.in for J>*> ll>v of mail. Thr hiplalir roinnnlly ,.,rri.-. p . t ~,,\, -nr for 
1 1..- triplane. equip|-d with three Liberty engines, has been fitted with a passenger rabln. with acrommodiition for 



inside and four others alwve. 



J-24 TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 

Perspective Sketches of the German Fokker Triplane 




The upper sketch shows a three-quarter rear view of the Fokker Triplane. This illustration gives a good idea of the gene 
arrangement of this interesting machine. Xote the small veneer plane enclosing the wheel axle. Below is a three-quarter frtl 
view of the Fokker Triplane. The thickness of the wings can be imagined from an inspection of this drawing. The pin-jointl 
struts are really ties rather than struts as they are working in tension 



SI.\(.I.K MOTOKKI) AKUOIM.AM 9 
The Fokker Triplane 






The Fokkcr triplane can IK- said to be of the " wire- 
ss " type. 

The internal construction of th. wings i^ .Jesigi,. 
ro\ iile nil the strength without anv external aid of anv 
tind. The interplane struts, which are really ties rather 
bin struts, might conceivably have been omitted alto 
rcthcr, and so tar as om is able to judge, their onl\ func- 
ion is to help to distribute the load more evenly b. tw.in 
he three wings. It is well known that in a biplane the 
ipp.r wing carries about four-sevenths of tin total load 
when the wings are of equal section, span, and chord > 
nd the lower wing about three scv enths. In a triplane 
tiucli the sum distribution is found, with the exception 
hat the middle and lower wing each take a share (not 
(|iial ' of the three sevenths of the total load. 

Ill the Fokkcr triplane the upper wing is of larger span 
han the middle wing, which in turn is of slightly greater 
pan than the low. r wing. In consequence, as the three 
iing~ appear to In- all of the same section, the upper wing 
itist carry more than four sevenths ot the total load. In 
rder to provide a licttcr load distribution, the middle and 
IIW.T wings are made to carry their share of the load 
n the top plane by connecting them to this ria thin high 
nen. ss ratio struts, which are in reality ties as they 
re working in ten* MI This explains why the struts 
re so ex) ninety thiii (about ' ._. in.) and the moment of 
nertia of the strut section would be so small that the 
truts would buckle under a very small load if subject to 
(impression 

The fact that no lift bracing is employed naturally 
wing spars of considerable depth if the spar 
rcight is to U' kept reasonably low. and in the Fokkcr 
riplane this has been attained by making the wing sec- 
ion very thick in proportion to the chord. Roughly, the 
i.ixiiiiiiin c tmh. r is in the neighborhood of one-eighth of 

T<1. 

wo wing spars are placed very close together, and 

ios. d in a box of three-ply wood. The function 

f this Itox is two-fold, it increases the strength of the 

l>-irs for taking bending and at the same time acts as 

it. rnal drift bracing. 

The upper wing, which is in one piece, runs right across, 

upported on struts sloping outwards as in the Sop- 

The other two wings each have a centre section 

igidly attached to the body, the middle one resting on the 

p longerons and the bottom one running underneath the 

wer longerons, an aluminium shield streamlining the 

>rmal surface presented by the deep flat sides of this 

imr. 

From the illustrations it will be seen that the gap is 

Uy small, being very considerably less than the 

liord. The inefficiency thus caused is partly made up 

staggering the wings but even so one would imag- 

ic tin- machine to be somewhat inefficient. The interfer- 

1 ing to too close spacing of the wings chiefly affects 

ie lift co-efficient, and as the machine is probably very 

:htly loaded compared with the majority of German 

>' bin. s it is possible that the landing speed is not 

Strictly speaking, the Fokker is not a triplane. It 



would be mon correct to term it a three-and-a-half plane, 
as the wheel avle is enclosi d in i . ising of plywood which 

M soincMhat similar to that of the . 

p.rnnints h.,\c shown Hint floats ,.| ,uch a sift ion as to 
ply cambered top surface may be made to sup- 
port their ,.wn weight during flight. In the case of the 
Fokker triplane it ap| irs probable thai tins pi 

around the wheel axh , not inconsiderable 

load during flight. Its section ap|>-ars capable : 
porting a fair load per square foot of area, and its in 
effici. i to low aspect ratio is probably less than 

one wo::!d expect in a plane of an aspect ratio of dmut 
two. on account of the proximity of the ,-ov, -red in wheels 
to the tips, the effect of which must he to stop end losses 
to a considerable extent. 

As regards the body of the Fokker triplane tins is con- 
structinnally very similar to that of the Fokker mono 
I lanes. I ongcrons as well as struts and cross ni.in 
lers are in the form of steel tubes, and are joined together 
by welding. The internal bracing of the body is pe- 
culiar in that the bracing wires are in appearance in 
duplicate, although they are not so in effect. 

The arrangement, to which we shall revert again when 
dealing with the Fokker in detail, does not appear to 
possess any other advantage than that in each bay only 
half the nuinlMT of loops II.IM to be made in the wires. 

The tail plane, as well as the elevators and rudder, 
is mode of steel, and is of a symmetrical section, much 
thinner than that of the Albatros, but otherwise similar 
to it in that no external bracing is employed. While thin 
is quite satisfactory in the Albatros on account of the 
thick tail plane spars employed, it appears wholly inade- 
quate in the Fokker, as the plane is very thin, and since, 
moreover, the trailing edge of the tail plane is a steel 
tube, which section, as is well known, is not a good one 
for laterally loaded beam, owing to the fact that much 
of the material is massed around close to the neutral axil 
where it in not taking very much of the load. 

As exhibited at the F.ncmy Aircraft View Rooms the 
Fokker is not complete inasmuch as the engine has been 
removed. The cowling shows without a doubt that tin- 
engine must have been a rotary, and the mounting 
the type usually employed for rotary engines, i.e., a main 
engine plate holted to the nose of the body . and a pyramid 
of steel tubes, supporting at its apex the rear end of the 
crank-shaft. A sheet of aluminium is placed immediately 
in front of the engine plate. The manner of cowling in 
the engine will be apparent from our illustrations, and 
docs not present anything of particular interest, follow- 
ing, as it does, conventional practice. 

Although they are not in place in the machine M ex- 
hibited, it is evident from the aluminium eastings for the 
cartridre 1 rlts that two synehronis. d ni-ichine-giuiH have 
hi en t.:-il, one on en h side above the fuselage. The 
usual tri;-:-i rs. operating the guns through How<!cn cables, 
are mounted on tie control lever, which latter is of the 
usual type. 

The following data relating to the weight of tin- ma- 
chine is given: Wright empty. :t?ii kg., useful load, 195 
kg., total weight, 371 kg. (about 1830 \b.). 



226 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Front view of the early form of Aeromarine Seaplane, showing the small head-resistance 

The Aeromarine Training Seaplane 



The seaplane is substantially the same as the land trac- 
tor, except that the seaplane has a slight increase in plane 
area. 

General Dimensions 

Span, upper plane \S ft. 9 in. 

Span, lower plane M ft. in. 

Chord 6 ft. 3 in. 

Gap 6 ft. 6 in. 

28 ft. 9 in. 

Height over all H ft. in. 

Weight, empty 1,400 Ibs. 

Speed range 77-43 m.p.h. 

Motor, Hall Scott " A7a " 100 h.p. 

Dihedral angle of wings, 1; Stagger, 1 ft. 6 in. There 
is no becksweep. Aspect ratio of top plane, 6.8 ; lower 
plane, 5.4. Wing curve, R.A.F. 6. Plane area, not in- 
cluding the two ailerons, 410 sq. ft. 

The body is 22 ft. 6 in. in length ; width, 34 in. ; maxi- 
mum depth, 3 ft. 6 in. Standard dual Dep control is in- 
stalled. 

The stabilizer is double cambered, non-lifting and non- 
adjustable; area, 50 sq. ft. Area of rudder, which is of 
the balanced type, 10 sq. ft. 



Twin pontoons are arranged catamaran style, centered 
7 ft. in. apart. They are of the hydroplane type with 
V bottoms and rounded sides and tops. Length, 16 ft. 
6 in.; beam, 30 in.; depth 17 in. A3 in. step occurs 7 ft. 
6 in. from the rear end of the pontoon. Air leads are 
built in to reduce the vacuum at the step. 

Material of pontoon is spruce, ash and mahogany, with 
double diagonal planking having layers of fabric between. 
The inside is divided into several watertight bulkheads. 

The power plant in the machine shown in the accom- 
panying illustrations consists of a Hall-Scott " A7a " 4 
cylinder, vertical, four-stroke cycle, rated 100 h.p. at 
1400 r.p.m. Bore and stroke, 5^4 in. by 7 in.; weight, 
410 Ibs. Fuel consumption per hour, 91/2 gallons. Oil 
capacity in crankcase, 3 gallons. Fuel carried for a flight 
of 4 hours' duration. The propeller is 8 ft. 4 in. in diam- 
eter. 

A streamline stack discharges the exhaust gases from 
the motor over the top of upper wing. This protects the 
passengers from the gas and keeps the machine clean. 




Side view of the early type of Aeromarine Seaplane 



SINCLK MOTOHKI) A Kl MM.ANKS 



-"-'7 




I KONT \ II.U 01 1111. I-"' II. I'. \l I>M AltINK NAVY TUAIMNC SI.AI'1 AM. 

Thr \rriim.iriin- Navy Training Seaplane. II is equipped with n Cnrtiss <>\ \<*> horse-power engine or the Acromarlne 
1 in Imrsr power I'liirinr. This seaplane is of the single float type, a development of the Aeromiirlne twin float Seaplane which ha* 
been iiM-il e\teiisi\ely by the Navy Department. With the single float the marhine is easy to manumrer on the water 




Thr Ai-roiiiiirinc MiMlrl 1(>-T Flyinfr Boat is provided with a 100 horse-power Curtiss OX enfrine. This mnrhine has Iwn <lr- 
rd I" answiT rri|iiiremrnt<i of thr sportsman. The Aeromnrlne 130 hor-.e-|iower Type I, engine is supplii-il whrn ilesin-il. 

Span of upper plane *8 fe.-t ; chord, 7.i in<-hcs; pap, 78 in<hcs; total weight 19i5 pounds; weight fully loaded, i.483 pounds. The 

wing floats have a buoyancy of 64 pounds. 32 gallons of gasoline are carried 



The Aeromarine "T-50" Three Seater Flying Boat 




1 Seating arrangement, showing the open cockpit for the pilot and the two rear passengers' seat* enclosed in a transparent 
cover, which protects the occupants from the wind and spray. The casing Is divided and hinrcd at the middle, permitting acceu 
from either side. 3 Stern post, rudder hinges and hull skid. 3 Aileron pulley attached to the lower left plane. 4 Engine 
IN. I. and attachment of middle struts. 5 Kighl wing float, built up of mahogany veneer with an ash frame. The bracing U of 
steel till*-, faired to a steamline form 



228 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Boeing Type C-l-F Seaplane 



Boeing Seaplan< 

The model C-l-F is an advanced modification of the 
Boeing type " C " seaplane used by the Navy Depart- 
ment for training purposes during the war. This ma- 
chine embodies the use of the single float and the Curtiss 
OXX-2 eight-cylinder motor. A further modification from 
the " C " type lies in the use of one degree of dihedral 
rather than 2% degrees as used on the older machine. 

Wing Structure 

The wing structure follows the model " C " in that a 
50 per cent, stagger and 2 1 /-; degree declage is used. This 
combination assures the inherent longitudinal stability 
which lias been characteristic of previous Boeing designs. 
The center cabane struts are made of seamless steel tub- 
ing with special steer terminals, giving a simple, efficient 
and sturdy center section construction. The forward con- 
struction of the cabane eliminates fore and aft stays and 
furnishes substantial means of bracing the side radiators. 
The interplane spruce struts are of straight streamline 
form, tapered at the ends to accommodate strut sockets, 
while the internal drift struts are made from web sec- 
tions, of box form. The wing fittings are of special de- 
sign, giving a minimum of head resistance, while provid- 
ing for maximum strength necessary. The wing tip floats 
are provided, these being of conventional form and se- 
curely braced to the lower wings. 

Tail Unit 

The design of this unit is characterized by extreme sim- 
plicity as well as maximum strength. Balanced elevators 
are used, giving automatic adjustment for differences in 
loading. This feature is particularly notable to pilots in 
that maximum and minimum conditions in the distribution 
of the useful load are unnoticed in flight. The elevators 
are fixed to steel shaft, having center and two end bear- 
ings for supports. Fin and tail posts are of steel, mak- 
ing a thoroughly satisfactory mounting for bracing and 
tubes. 

Landing Gear 

The landing gear is of conventional single float type. 
The underwater lines of this float are such as to asssure 
quick get-away and easy landing without undesirable 



-Type C-l-F 

spray and water disturbances. The stability of this ma- 
chine has frequently been demonstrated while taking off', 
landing and taxying in rough seas and while drifting in 
as high as 30-mile winds. The float is of two-ply lami- 
nated construction and with cotton and marine glue be- 
tween the laminations. The external float fittings are 
such as to facilitate rapid assembly as well as to trans- 
mit all stresses to the center longitudinal bulkhead, which 
is the main strength member of the float. The landing 
struts are of streamline steel tubing. 

Body 

The body is of the conventional longeron truss type with 
metal frames for engine bearers and metal carry through 
struts for lower wings. The seats are made from a series 
of ash slats conforming to the attitude of the occupant 
and covered with detachable upholstery. The cushions 
are stuffed with Kapoc and are readily detachable for 
use as life preservers in emergency. The instrument 
board is equipped with all instruments necessary to indi- 
cate the operation of the machine. The surface control 




The Boeing Type C-l-F Seaplane 



SIMJI.K MOTOUKI) AKU01M.AM.N 



The Hociiin Type III 

pi. in.- iili Carttai n\\ .- mnt.i 




is Dn.-il Dep.-rdiissin. featuring an adjustable rudder and IP|HT I'lan.-s (includinir Ailrrmis) M4iq.ft. 

adjustable rudder compensator for distance service Tin- I "wer I'lnn- . . J9 q. ft. 

engine throttle is mounted a. the right of both ebckpte, Nu^.-f Ail.-r *"' " 

e Ignition retard is at th<- l.-ft of the pilot's cock- Ki,-vat,.rx aotq.rt. 

pit. Tin- ( Urtiss OXX J MX) li.p. motor has proven ex- Hu<llrr Uiq.ft. 

trrinrly satisfactory. It is lijfht, powerful, economical Vertical Kin . 6 nq. ft. 

and fr.-r from undesirable vibration in the ranjp- of Hvinfc 3 - Or "'' 1 " l>imrn*iatu 

operation. A hand starting lever is provide,! iminediatelv Sp " n , ri>|K ' r , 1 ^' in ' ? ' ' ** " " 

,..,,. .spn Lower \\ me U ft. 11% In. 

behind the motor and has ,. sa t,sfactory service. As ,-,,, , ,, |M . r n * d ljomtT wln)t 

Mentioned before, the cooling system is mounted to the Gap 7.- in 

rear and above the motor. This mounting is exceptionally l^-ntfth over all .>: n. iii-p. in. 

eOVetive ; ind l,as performed .satisfactorily in service. The H-i|flit ovrr all . . I i ft. 1 1 </, to. 

IMS, .line t.-mk is iuiinediatelv Ix-hind the motor and sup- ' <lr ' 

. . . . rtiAffrr J9 y t in. 

ph.s gasoline under atmospheric pressure to the carbu- Incidence ,.f up|K-r wlnp SV.drjf- 

retor. The carburetor lead is supplied with a shut-off Incidence of lower winjrn tdr|r. 

% f lve operated from either cockpit as well as a con- 4. I'rrfnrmnnrr 

\enient drain l.< n< atli the body Climb In 10 minutrx (full load) IflOO Frrt 

Mi^h s|xfl TOM. P.M. 

Performance Ijtndinir snrrd 38 M.I' II 

I l',,-,crr Plant - Knduranrr t full uprrd 2% hour* 

Curtiss OXX-9 100 h.p. 5 Wright 

2. H'IFK; ami I'unlrnl Surfnrr Arm* IJomded 844S lb* 

.Main Planes (including Ailerons) 493 sq. ft 




THEBUR.GE55 SEAPLANE 

MODEL HT- 2 

SPEED SCOUT 



5cale of feet 



McLaughlir 



230 



SI\(;i.K MOTOHKl) .\KK01M..\\ES 



2-.ll 



The Burgess Speed Scout 
Seaplane 




Tlirrr-<|iuirtrr front vlrw of the Burgrai pel tcoul sraplanr 



Our f tin- neatest scout machines of American manu- 
facture is (In Hurges.s HT-2 .seaplane. Tlie Burgess Com- 
pany's experimental works ha.s dcvvlo|ied and perfcetnl 
a numlirr of original construction features in this scout, 
the must -ipp.-irrnt of which nre the struts between the 
planes .-ind td tin- Huats. (he shock-absorbing float system, 
and a detailed elimination of sharp angles by means of 
li.-ils-i umnl streamlining. 

General Specifications 

Winjr span, upper 3* ft. 4 in. 

\Viii)T sp.ni. luwcr il ft. 6 in. 

\Viii(t chord. IM.HI pl.mes 3 ft. 6 In. 

Gap llrtweell pliitles 4 ft. in. 

Height nvt-r all 10 ft. in. 

Ix-npth oevr ll -'-' ft. : in. 

M..l,,r. Curtiss OXX-J 100 h.p. 

Maxiniimi speed 95 in.p.h. 

Lnndiiifr speed 40 m.p.ti. 

Planes 

There is no dihedral, stagger or swecpback. The upper 
plane is in four sections, the central sections joined by a 
pair of metal plates at the wing spars. Each section 1 1 
ft. in. long. Outer or overhanging sections, to which 
the ailerons are attached, are each 5 ft. 10 in. long. 

The lower plane sections extend 9 ft. -I in. at either side 
of the fuselage, which is SO in. wide at this point. Ribs 
are spaced 9 in. apart. The forward main spar is cen- 
tered 8 in. from leading edge; spars centered 20 in. apart; 
and the trailing edge is 1* in. from the center of rear 
spar. This totals to 42 in., the chord of the plane. 

Internal drift wires are terminaled to the ends of ta- 
pered compression struts, the ribs being relieved of this 
strain. Overhang brace wires and intcrplane brace wires 
are doubled, and the space between filled with spruce 
streamlining strips, the edges of which are routed out to 
receive the wires. 

The struts are K shaped, built up of spruce and cov- 
ered with fabric. In forming the strut, one spruce member 
runs from below the upper rear wing spar to top of lower 
forward wing spar; another member runs from below 
upper forward spar to lower rear spar. This forms an 
X A third member between the upper and lower forward 
spars gives the K shape. The ends are filled in to a 



HI,, I 



curve with balsa-wood, doing away with the n 
producing a streamline effect. 

Body 

The forward part is covered with louvred sheet alumi- 
num in the usual manner. The circular radiator at the 
nose is 27 in. in diameter. The sides and top of the 
body arc curved beyond the longerons by means of thin 
horizontal strips of spruce, supported on formers, and 
covered with fabric. The top is provided with a semi- 
elliptical streamlining ridge starting at the pilot's In ul 
n-st. The top of the body is in sections, which are sep- 
arately removable. 

The pilot's cockpit is exceptionally deep and roomy. 
Deperdnssin control is installed; the aileron control passes 
through the sides of the body at a point 12 inches above 
the lower plane, on line with the forward edge of .struts. 
running to the top of the K strut, thence to a pulley at- 
tached to the underside of the upper wing spar, and then 
to the aileron crank. Control wire openings in the body 
are protected by heavy skin washers, sewed to the fabric. 

The cockpit top, above the instruments, is formed with 
celluloid, giving ample lighting to the cockpit interior 
and at the same time providing a satisfactory wind shield. 

Tail Group 

The rear spar of the tail plane is 1 1 ft. () in. long. 
Solid wire braces run from both the forward and rear 
spars to the top rear end of the vertical fin, and also 
from underneath the forward spar to the tail float. 

The root of the vertical fin is built into the curved fuse- 
lage top. The rudder has a small balancing surface for- 
ward of the hinges, the lines of the rudder continuing 
from the curve of the fin. 

The pair of stabilizers are attached to a single forward 
spar, causing them to work in unison. Control crank 
arms are 9 in. high, with a pair of solid brace wires to 
each. 

Floats 

Main floats are 11 ft. in. long, 3 ft. in. wide and 
17 in. in maximum depth. They are spaced 6 ft. 6 in. 
from center to center. The forward horizontal strut be- 
tween the floats is located 2 ft. 2 in. from the bow, and 
the rear strut, which acts as a shock-absorbing axle, 7 ft. 



232 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




Side view of the Burgess UT-2 speed 
scout seaplane 



2 in. from the bow. Struts run from the forward hori- 
zontal strut to points near the radiator. The rear axle 
is at the lower termination of the V struts, which run 
from the fuselage and the lower plane, continued in the 
K strut to the top plane. This axle is attached to the 
float by rubber cord, with metal guides to allow for the 
vertical movement of the axle. By means of this system 
of shock absorbing, much of the porpoising has been 
eliminated when taxi-ing, and many of the hard landings 
are entirely taken up by it. 

Hand holds are provided at each compartment, screwed 
flush with the deck. Mooring rings are attached at the 
forward end of each float. A step occurs just below tl-e 
rear axle with a 2 in. air duct run through the float to 
prevent suction. 

The main support for the tail float is provided in a 
26 in. extension of the fuselage termination which is 
streamlined fore and aft, to a width of 7% in. A pair 
of struts 24 in. long are located 15 in. from the front 
of tail float, and bracing wires run from their upper 




The shock-absorbing float support 

ends to the lower end of rear strut. Overall length of 
pontoon, 4 ft. 6 in., width ll 1 /^ ' n -> depth 12 in. 

Motor Group 

The propeller, designed by the Burgess Company es- 
pecially for the speed scout, is 7 ft. 9 in. in diameter, 
with a 5 ft. 9 in. pitch. The motor is a Curtiss OXX-2 
rated 100 h.p. at 1400 r.p.m. Fuel is carried for a flight 
of 2*A hours' duration. 




Curtiss Model H-A Mail Machine. Streamline has been carried to a very effective degree on the Curtiss Model H-A Mail 
Machine. The fuselage is exceptionally deep, wings being attached directly to the fuselage and a single pair of struts at either 
side. A Kirkham model K-12 engine is used, connected to a four bladed propeller with high pitch. The photograph fhows the neat 
way in which exterior control wires have been eliminated. 



SINUI.K MUTOKKI) A Kl{< )1M..\NKS 




I In- I 'nrti-s Mmli-l 1 1- A 1 1\ dm An unusual fr.iture in this III.H him- is ||M- sinjrlr pair of struts from thr pontiMia In tin- fiisrlagr, 
tin- dr<-|> liody anil tin- cliiiiiiiiitinn of struts lx-trcn tin- wii>|is ami Inxly. Thr II|>|T ]>lanr hits the customary (xisjtjvr ilili.-.lr.il hut 
the Inw.-r planes slo|..- downward in n negntivi- or rrvrrsrd dihedral. Thr Hydro rrrinli|rs in many respects thr H-.\ l-and Ma- 
<-liim- l>nt two sets of struts iirr used on thr Hydro l>ecmisr of the greater span. 



The Curtis* H-A Hydro 



Tin- ( nrtiss II \ Ilvilni is a two plan single flont sea- 
l>lain-. Tin- upper wing has > dihedral of S r and the 
lowi r pl.-uir a i-atlii-ilral of 1. Both plant's have an in- 
rnlrnri- of .' . a ml a swri-pliack of t'j . In official tests 
l<\ tin \ ,\ \ I > partiiu-nt tins inncl)ine ha.s made a sprcil 
of l.il.'i miles per hour with a full load. Its climbing 
spi . il li S.'.IMI t, it in ti-n iniiiiiti-s. 

1 hi final is jii f.Tt long, .H ft. 6 in. wide and 4 ft. 6 in. 
ili i p. It has thri'i- planini; strps. 

The horizontal .stahilixer is adjustable during flight, 
within tin- limits of minus and plus 1. The machine 
i-arrii s four machinr-giins; two fixed Marlins and two 
hYxilih I.i w is 

Th. rimiiii- has a Liberty 1'-'. giving 330 h.p. It is 
<lir.-.-tlv eoniieetrd to a two-hladrd propeller 9 ft. -J in. in 
di uneti-r. with a 7 ft. 7 in. pitch, or a three-bladed pro 
peller s ft. ti in. in diameter and 7 ft. 6 in. in pitch, de- 
pending upon whether speed or quick climb is required. 

The general specifications are as follows: 



l'l>l>er plnne .................................... 30 ft. 

l.owrr plnne .................................... 36 ft 

Cord ........................................... 7* in, 



Maximum ftp 

Minimum (rnp ................................... 4i'/, 

Overall hriffht ................................... 10 ft 

( Id-mil Irnnth ................................... 30 ft 

Arrn, upper plnne ............... IM.fl 

A rrn, lower plnne ............................... 170.8 

Total siip|Ktrtlnf( area ........................... 390 

A rrn of rach nlleron ............................. 8.6 

Totnl nllrron nrrn .......................... . 34.* 

I lorinnntal -t.iliiliwr ............................. M 

Vrrtlrnl stnhlltaer ............................... 18J 

Itucltler ......................................... l-'i 



o In. 

in 

in. 
In. 

7 In. 

9 In. 
,. ft. 
,. ft. 

V| ft. 

-I ft 

,. ft. 

q. ft 
M|. ft. 
q. ft. 



Weights 

Welftht per .sq. ft -3i H>s. 

Wei(rht per h.p H-4 ! 

Nrt wrlfrht, machine empty 1,6218 Ihs. 

Weiirht, full load I.OI8 H. 

Performance 

Speed range 6i to 131.9 m.p.h. 

Climb 1,000 ft. per minute 




Thr Curtis., Model II-A Hydro aeroplane, which is rnted to hive a perd range of from 61 to 130 mile* per hour 




,330 HP LIBERTY 

FLYING BOAT 



Jci.le of feet 



10 a 14 I 



234 



SIXCLK MOTOKK1) A KK< )I>I ..\ M S 






An IIS -' I. anil other types of American flying boats mid seaplanes taking off in formation 



Curtiss Model HS-2-L Flying Boat 

In order to increase the amount of load carried, the 
MS I f. type of mncliine was given additional wing sur- 
f in .-uid tliii-. lr:mie the IIS v.' I.. The speed was not 
r<ili:i-.-d liy tliis change. The climbing power was con- 

-ider.-ililv increased. 



General Dimensions 

iii^ S|.:ui fpper IManr 74 ft. 0>%j In. 

ine Span - Lower Plane 64 ft. 121 ; fe, In. 

Depth of Wine rhoril 6 ft. 3%, In. 

dap U-twccn Wine* (front) 7 ft. 7% in. 

Cap ln-tween Wines (rear) 7 ft. 52% 2 In. 

_! r None 

Length of Machine- overall 40ft. 

Height of Machine overall 14 ft. 7'/ 4 In. 

Alible of Incidence t'pper Plane 5 1 /, degrees 

le of Incidence I.ower Plane 4 degrees 

Dihedral Angle 2 degrees 

;ihack degrees 

ine CIIMC R. A. F. No. 6 

Horizontal Stabilizer Angle of Incidence degrees 

Areas 

- I'pper 380.32 sq. ft. 

- I-ower 314.92 sq. ft. 

Ailerons (upper 62.88; lower 42.48) 105.36 sq. ft. 

Horizontal Stabilizer 54.8 sq. ft. 

Vertical Stabilizer 19.6 sq. ft. 

tor, (each J.'.s sq. ft.) 45.6 sq. ft. 

Rudder -''5 sq. . 

I Supporting Surface 8O0.6 sq. ft. 

g (weight carried per sq. ft. of support- 7.77 Ibi. 

ne surface) 

Loading (per r.h.p.) 18.84 Ibs. 



Weights 

\.t Weight Machine F.mpty 4,349 Ibs. 

Gross Weight Machine and Load 8.M3 Ibs. 

Useful I^ad 1^64 Ibs. 

Kurl 977 Ibs. 

Crew 360 Ibs. 

Useful loud . 527 Ibs. 



Total 1.864 Ibs. 

Performance 

Speed Maximum Horizontal Flight 91 miles per hour 
Speed Minimum Horizontal Flight 54 miles per hour 
( limbing Speed 1,800 feet in 10 minutes 

Motor 
I.ilH-rty 1 -.'-Cylinder. Vee. Four-Stroke Cycle .... Water cooled 

Horse' Power (Rated) ' 330 

Weight per rated Horse Power 3.55 Ibs. 

Bore and Stroke 5 In. x 7 In. 

Fuel Consumption per Hour 32 gals. 

Kurl Tank Capacity 152.8 gals. 

Oil Tank Capacity 8 gals. 

Fuel Consumption per Brake Horse Power per 

Hour 0.57 Ibs. 

Oil Consumption per Brake Horse Power per 

Hour 0.03 Ibs. 

Propeller 

Material Wood 

Pitch according to requirements of performance. 
Diameter according to requirements of performance. 
Direction of Rotation (viewed from pilot's seat) Clockwise 

Maximum Range 
At economic speed, about 575 miles. 




Front view of the HS-2-L equipped with a Liberty "IS" motor 



236 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 





The Curtiss Model HS-1, which was the forerunner of tin- The Curtiss Model HS-1 in flight, making a speed of 76 mile 
HS 2-L an nour 




The HS J-L, equipped with a Liberty motor. The wing spread of the HS 1-1- was in- 
creased to lift a greater load. A counterbalanced rudder was also added. This type 
of machine was used for patrol duty in this country and also as a training plane for the 
pilots of the H-16 and F 5-L boats. 




Side view of the HS 2-1.. It has been found that only one set of ailerons on the 
upper wing only is sufficient to handle the machine. The use of this boat for combat 
purposes is limited because of its unprotected rear portion. As a patrol scout it car- 
ried two bombs, beneath the lower wing, one on each side of the hull. The crew con- 
sists of two pilots and an observer in the front cockpit 





IOOHPCURTISSCKX 

FLYING BOAT 

ScaJ of feet 



Mn-Hn 



237 



238 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




CURTISS MODEL M. F. 
FLYING BOAT 

The Navy Department has em- 
ployed a great number of the M. 
F. Boats for coastal training 
work. Machine is well suited for 
marine sportsmen for it is com- 
paratively small and is easily 
handled. The boat is provided 
with either a Curtiss OX 5 100 h.p. 
engine or the new Kirkham K-6 
150 h.p. six-cylinder vertical en- 
gine. The M. F. Boat is an im- 
provement in design over the Cur- 
tiss F Boat which found so much 
favor before the war stopped 
civilian flying 



Curtiss Model MF Flying Boat 



This machine is suitable for general and sporting use. 
It is an improved form of the F boat. 

General Dimensions 

Wing Span - Upper Plane . 9% in 

Wing Span Lower Plane 3 8 '%2 >' 

Depth of Wing Chord . > 6 ' 

Gap between Wings at Engine Section 6^ ft 4% 4 i 

Length of' Machine' overall ".'.'.'.'.'.'.'.'.'.'. 28 ft. W in. 

Height of Machine overall 11 ft. 9% to. 

Angle of Incidence " degrees 

Dihedral Angle, Lower Panels only 2 degrees 

Sweepback Xone 

Wing Curve U- . A. No. 1 

Horizontal Stabilizer Angle of Incidence ... degrees 



Areas 

Wings Upper 

Wings Lower 

Ailerons (each 22.43 sq. ft 

Horizontal Stabilizer 

Vertical Stabilizer 

Elevators (each 15.165 sq. ft.) 

Rudder 

Total Supporting Surface 

Loading (weight carried per sq. ft. of support- 
ing surface) 

Loading (per r.h.p.) 



187.54 sq. ft. 
169.10 sq. ft. 
44.86 sq. ft. 
33.36 sq. ft. 
15.74 sq. ft. 
30.33 sq. ft. 
20.42 sq. ft. 
401.50 sq. ft. 
6.05 Ibs. 

24.32 Ibs. 



Weights 
Net Weight Machine Empty ............... 1.796 Ibs. 

Gross Weight Machine and Load ........... 2,432 Ibs. 

Useful Load ............................... ^6 Ibs. 

Fuel ............................. ^ lbs ' 

22 ' 51bs - 
3fi lbs ' 



Oil 
Water 



Pilot .......................... 16S lbs ' 



Passenger 

Miscellaneous Accessories 

Total 636.0 lbs. 

Performance 

Speed Maximum Horizontal Flight 69 miles per hour 
Speed Minimum Horizontal Flight 45 miles per hour 
Climbing Speed 5,000 feet in 27 minutes 

Motor 
Model OXX 8-Cylinder, Vee, Four-Stroke Water cooled 

Cycle 

Horse Power (Rated) at 1,400 r.p.m B 

Weight per rated Horse Power *-01 

Bore and Stroke 

Fuel Consumption per Hour 1' 

Fuel Tank Capacity * g" ls - 

Oil Capacity Provided Crankcase 

Fuel Consumption per Brake Horse Power per 

Hour .... - 60 lbs ' 

Oil Consumption per Brake Horse Power per 

Hour ... - 030lbs - 

Propeller 

Material Wood 

Pitch according to requirements of performance. 
Diameter according to requirements of performance. 
Direction of Rotation (as view from pilot's 
seat) Clockwise 

Details 

Dual Control. 

Standard Equipment Tachometer, oil gauge, gasoln 

Maximum Range 
A', economic speed, about 325 miles. 



SINCil.K MOTOKK1) AKHOIM.AN KS 



.. 




I In Inn I, p l.ilxTty motored (iallnndet !)- lijjlit 1'iuiilxT -enplane 



The Gallaudet D-4 Light Bomber Seaplane 



Tin- Gallaudet D-J Light Bomber Seaplane uses a 
single KK> li.p. Liberty " Twelve " engine. 

Si \ir.il n-tiiu -incuts in detail have Ix-en incorporated 
in the IK w design, .., M ,l it is probable that the Gallaudet 
is now tin fastest sr.-iplnne ever built. Its maneuver- 
ability is exceptionally flexible, in spite of difficulties 
usually encountered in seaplane design. 

On Deeeinber IsJth a series .if tests of the !)- Sea- 
plane were carried out during a two-hour run over Narra- 
gansi It Hay liy the I'. S. Navy. The tests show the ma- 
chine to be capable of cruising at 78 miles an hour, while 
the engine turned at 1360 r.p.m. At this speed the fuel 
consumption was 16 gallons per hour, and the cruising 
radius 7.19 hours, in which time a distance of 561 miles 

could lie emered. 

General Specifications 

Span, upper plane 16 ft. 6 in. 

ClK.nl. Ix.th planes 7 ft In. 

t ween planes 7 ft. in. 

Total winjf area 6H sq. ft 

Wrijrht. iimchinr empty 3JWX) ll. 

of useful load ' 1.600 \\>-. 

Wri^ht. fully loaded i,4OO Ibs. 



Maximum sprrd I .'(i m.p.h. 

Slowest landing: 4.'. li m.p.h. 

Slowest p-taway 46.0 m.|>.h. 

Climb in two niinutr* J.UMI ft. 

Klyinjf rndiu.s at full power 3 hours 

The useful load is made up of the following: 

Water I l.i Ibs. 

Pilot and observer :O Ihs. 

Fuel and oil (UO Ibs. 

( Irdnance 9.5 Ibs. 

Bombs 390 Ibs. 



Total 1600 ll.s. 

The fuselage is of streamline form, with a circular iec- 
tion bullet nose. Steel tuliinjf is employed in the frame- 
work. 

At the forward end the gunner's cockpit is located. A 
flexible searfed ring for mounting twin Lewis machine- 
guns is placed around the cockpit. A very wide are of 
fire is provided for the gunner, and an unobstructed view 
is obtained by both pilot and gunner. 

The engine is located aft of the pilot, between the up 
per and lower planes. It drives a ring surrounding the 



The GMlaudet D-4 leaving the 
water for a flight. Note the 
> i' k of the wings 




240 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




fuselage, to which the four-bladed propeller is attached. 

This construction is unique in that it permits the ad- 
vantages of an enclosed fuselage usually employed in 
tractor machines, while the screw is placed in pusher 
position, permitting an advantageous placing of occupants 
and engine. 

Planes are flat in span and similar in plan, but ailerons 
are placed on the upper plane only. Planes have a mod- 
erate stagger and a pronounced sweepback. 

The center section of the upper plane contains a 38 
gallon fuel tank with a supply pipe running straight down 
to the engine below it. 

A 75-gallon fuel tank is placed in the main float at the 
center of gravity. The fuel system employs twin wind- 
mill pumps with overflow return. 

Two radiators are located in the center section at either 
side of the gravity fuel tank. They are set into and con- 
form in outline to the wing section. 

Central pontoon or main float is built up of mahogany. 
It has 16 water-tight bulkheads or compartments. The 
two wing tip floats each have five compartments. 



GALLAUDET D-4 BOMBER 

The Giillaudet Bomber has a Lib- 
erty Engine of 400 h.p. driving a 
four-bladed pusher propeller. The 
machine is a two-seater with pilot and 
observer placed well forward. Fuse- 
lage finely streamlined and the plac- 
ing of the lower wings below the 
fuselage brings the center of thrust in 
a very desirable location. A maxi- 
mum speed of 126 m.p.h. and a climb 
of 2,100 feet in 2 minutes was re- 
corded in an official test flight 





The Gallaudet D-4 in flight over Narragansett Bay 




The Curtiss K-9 Seaplane, equipped with the Curtiss V-2 200 h.p. motor 



SIMiLK MOTOKK1) .\KHUIM..\NKS 



Typ< 



Thomas-Morse 
-S-5 Single-seater Seaplane 



Gener?! Dimensions 



I.cnjrtli 
Spread 

II. it-lit 



.'.'ft 'tin. 

.''. ft. ' in. 

!l ft. T in. 



Weight and Lift Data 

Total weight loaded 1500 Ibs. 

Arm lifting surface (including ailerons) JiO sq.ft. 

Loading per square font nf lifting surface 6.::> HIS. 

Keijuired horse power 105 

eight i>f in.irhiiir loaded IMT h.p U.:i His. 

.Power Plant 
Type nf engine 100-h.p. Cinornr (air cooled rotary) 

n^'ine rrMiliitiniiK |iT liiinuti- 

Furl capacity, 'Mi (.'all. ins. sufficient for :{ liours' Hijfht at full 

power 

Oil capacity. ii..'i gallons, sufficient fur .'!'_. liours' flight at full 

poucr 

rn>|M-lliT t\ pi- 3 blade 

I'niprlliT diameter 8 ft. 

Propeller rcMilutions |>rr minute 1350 



Chassis 



Ty I M 



.Twin |M>ntiMins and tall float 



Area Control Surfaces 

Ailerons: (two) 30 sq.ft. 

Klrv aturs ii gq. ft. 




The Thomas-Morsr S-i Seaplane about to make a lundlng. 
Motor: Gnome 100 h.p. 



f.S sq ft. 

Horixontal stahiltcer 16.H tq. ft. 

Vertical stabiliser 3.5 q. ft. 

Stick type control used. 

Performance 

speed 93 milrs ]HT hour 

speed M mile* per hour 

Climb in first trn minutes 6JOO ft. 



Navy M-2 Baby Seaplane 



Tin \l j S, -ipl.-uif d, M^'ii.'d by the Navy Department 
as 1. 1 hn. !>< t M used for sulimarine patrol work. It in 
tli<- sui ill. st s, ,-iplane ever built, and its size has gained 
for it thr ii.iini' of " niolrrule." It is easily set up and, 

eupyin^ -ii little space, can be stored aboard a sub- 
iiiariiu-. 

Tin- in.-u liiii.- is a tractor monoplane with twin floats. 
The |il uir has a span of 19 ft., a chord of -I ft., and n 
total w iii>r aren of only 72 square feet. The wing section 
is a modified K.A.F. 15. Overall length of machine 13 
ft. 

Tin- floats .-ire 10 feet long and weigh 16 Ibs. each. 
I'lii \ are eoiistructed of sheet aluminum with welded 
seams. The interior of the floats is coated with glue 



and outside is not painted but coated with oil. F.xperi- 
ments have proven this practice to be most efficient in 
preventing corrosion. Floats have exceptional reserve 
buoyancy: with machine at rest on the water it i-. ini 
possible to overturn machine by standing on the wings 
near the tips or by standing on the rear of the fuselage. 

The engine is a S cylinder Ijiwrence 60 h.p. air cooled 
engine, driving a 6 ft. 6 in. propeller with a 5 ft. pitch. 
12 gallons of gasoline and I gallon of oil are carried, 
sufficient for .' hours' flight. Fully loaded with pilot and 
fuel the complete machine weighs but .ion pounds. The 
maximum speed is about 100 m.p.h., and the low s|>eed is 
.'>(> m.p.h. 



The Curtiss R- twin pontoon 

rap). in.- equipped with a C'urtivs 

-I lip. motor 






THE FRENCH FB.A 

HISWO-SUIZA MOWED 

FLYING BOAT 



Sc.l. of ft 



Mclaughlin 



242 



SIN(;i,K MOTOMK1) AKK01M.AM - 



TIli- I '. B \. 11} in,; boat, lln 
t>pe nf liu.-it u.i^ useil extensively 
fur over-water lifililiii); In the al- 
lies, iinil lias proved MT\ sitisfac- 
lurx . 




The F. B. A. Flying Boat 



This boat, equipped with Gnome . Clcrget or niorr often 
Ilispaiio-Sui/a en-m. s. In- pro\ ed In !>< fast anil .l! 
suited fur lii-li speed coastal Hying. All the Allii-s. lint 
more p:irtinil;irly Franc.- and Italy, largely used the FBA 
!>(> it-, fur en er water fighting, and much good work has 
IHTII dune with it. 



General Specifications 

Spin, upp,-r plain- 47ft. 614 in. 

Span, lower plane 3i ft. 8-Tf, In. 

Clniril, upper plain- 6 ft. {, In. 

Clinril. lower plane iff. :J in. 

Cap between planes 5 ft. 9%;, in. 

Length overall 33 ft. :,,; in. 

t overall 10 ft. 8U, in. 

Net weight, machine empty 150O Ihs. 

iiross weight, machine and load 1600 Ibs. 

Knjrine, Ilispano Suiza 150 h.p. 

Propeller, iliameter ft ft. 6 in. 

Speed ranjre 99-45 m.p.h. 

('limbing speed 3300 ft. per min. 



Main Planes 

Main planes are not staggered and have no sweephack 
nor dihedral. Fnd.s are raked at a 13 angle. In, i 
1, nee angle of upper and lower planes, 3. 

L'pper plane is in three Dictions; lower plane also in 
:hree sections. 1'pjx-r and lower center wing panels are 
7 ft. 8 :t s in. long. I'pper outer panels 19 ft. 10% in. 
ong; lower outer panels \'t ft. () in. 

Centers of inner interplane struts located 8 ft. 9 3/16 
n. to either .side of the centerline of the aeroplane; inter 
nediate struts centered 5 ft. -.' 13/16 in. from inner struts; 
niter struts centered 6 ft. 8 in. from intermediate struts. 
Slanting struts carrying the overhang of the upper wing 
lave their upper ends centered 5 ft. 1 1 in. from outer 
truts. This leaves a 2 ft. 7 1/16 in. overhang at each 
ring-tip. Overhang on the lower wing. 2 ft. 73/16 in. 

Chord of the upper plane. 6 ft. 2~' s in. Front wing 
warn centered 7~x '" from leading edge; beams centered 
! ft. II 7 '16 in. apart. Distance from center of rear 
icam to rear of trailing edge, 2 ft. 7 916 in. 

Chord of the lower plane, 5 ft. 3 in. Beam spacing 
rom the leading edge is similar to that of the upper 



plane. Distance from the center of rear beam to tin- 
trailing edge. 1 ft. 7 7 16 in. 

Ailerons on the upper outer wing sections are 2 ft. 
7 ! Hi in. wide and H ft. I i:> 1C, in. in spnn. 

For propeller clearance the upper plane is cut away 
for 9 ft. 10 :l s in.; from the lower plane a portion 4 ft 
.S'o in. wide is cut away. 



Hull 

Overall length of the hull, 30 ft. 2 I 16 in.; maximum 
width, at rear of cockpit, t ft. 33/16 in. The planing 
step on the bottom of the hull occurs 10 ft. (>>* in. from 
the nose. The nose extends 8 ft. 6-% in. forward of the 
leading edge of the wings. Bracing rabies run from the 
nose to the tops of forward intermediate interplane struts. 

Provisions are made for carrying a pilot and passenger 
seated side-by-side in the rear cockpit, and a passenger 
or gunner in a cockpit forward in the hull. 

Wing-tip floats arc placed directly below the outer hi- 
terplanc wing struts. 



Empennage 

The empannage or tail group is supported by a set of 
.struts from the upturned termination of the hull. The 
horizontal stabilizer is set at slight positive angle. It 
is semi-oval in outline, its front edge located it ft. I I :< 16 
in. from the trailing edge of the main planes. From front 
edge to trailing edge it measures 5 ft. 2 13/16 in. 

The elevator or tail flap consists of a single hinged 
surface 3 ft. 117 16 in. wide and 8 ft. In'^. in. in span. 
It is actuated by two pairs of small diameter tubular steel 
pylons at either side of the rudder. 

The rudder, of the balanced type, is mounted above 
the tail on a pivot situated I ft. 1 ' j in. forward of the 
tail flap. It extends |u <i 1(5 in. forward of the pivot and 
3 ft. 11 7/16 in. aft of the pivot. This brings the rear 
edge of the rudder 6 9/16 in. beyond the tail flap trailing 
edge. 

Four bracing wires run from the top of the rudder pivot 
to points where the tail is supported from the hull. Con- 
trol wires to the rudder and tail flap run into the hull 
through a single control wire outlet in the deck. 



244 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Italian Savoia Verduzio 168 h.p. 
Reconnaissance flying boat 



The Italian Macchi Flying Boat. The 
total surfaces are supported upon struts 
and braces. 






GEORGES LEVY 

TYPE R *">RfNlUlT 

FLYING 60AT 



Mtr 



McLikujklin 



245 



246 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




The Georges Levy Type R Flying Boat, equipped with a 280 h.p. Renault Engine. Span, upper plane, 18.5 meters; lower, 
12 meters; total length, 12.4 m.; overall height, 3.85 m. ; lifting surface, 68 sq. meters; stagger, 138 mm. .5; weight empty, 1450 
kg.; useful load, 1000 kg.; speed, 145 km. per hour. 





Method of folding the wings of the Georges Levy Type R flying boat 




The Georges Levy two-seater flying boat " Alert," with a Hispano-Suiza engine. This is a lighter boat than the Type R. 

Both types have the folding wing feature. 










AUSTRIAN AGO TYPE 

210 H.P. 

5EA PURSUIT BIPLANE 



Scat. <f M.t* 



247 



248 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Austrian Ago Flying Boat 



In its general lines this machine does not differ much 
from all the flying boats of the Ago type. It does offer, 
however, features that are original and worthy of men- 
tion. Most striking is the structure of the wing cell in 
which no wires are employed. 

The wing cell may be considered as consisting of two 
cross-networks, each made up of a front spar and a rear 
spar and of adjacent struts in inclined planes connect- 
ing the spars, all converging toward the center of the 
" star " located midway between upper and lower wings. 
The struts are of polished steel tubing with a fairing of 
laminated wood less than one mm. thick, providing a good 
streamlining effect. 

General Dimensions 

Span, upper plane 8.00 meters 

Span, lower plane 7.38 meters 

Chord, both planes 1.50 meters 

Gap between planes 1.65 meters 

Length overall 7.62 meters 

Length of hull 6.50 meters 

Maximum width of hull 1.00 meter 

Motor, Warschalowski 218 h.p. 

Propeller, diameter 2.72 meters 

No lists of weights or performances are obtainable. 

Control cables to the ailerons pass close to the struts 
of the turret and lead to the upper plane. Each aileron 
is about 1.40 meters long and .40 meters wide. 

The construction solution of the hull, the great care 
with which the exposed parts have been shaped, the com- 
plete covering of the cables and control wires, and the 
streamline shape of the hull, all show a desire to cut down 
head resistances as much as possible. Similar care is 
shown in all details of construction to reduce to a mini- 
mum the weight of the machine without detriment to its 
strength. 

The hull is 6l/-> meters long; vidth at the step, .95 
meters; maximum width, 1 meter; distance from bow to 
step, 8.45 meters; height of step, .16 meters. The shape 
of the body wtth the necessary lining .at the bow and 
because of a careful laying of the side and bottom plating 
approaches very much the shape of a solid body of fairly 
good streamline form. The wing floats are spaced 5 
meters a"art. They are of streamline section, with flat 
sides, attached to the planes by means of one forward 



strut and two rear struts, with cross wire bracing be- 
tween the struts. 

The empennage or tail group is 2.38 meters in span, 
sustained in front by a vertical fin of very thin laminated 
wood, by two stays and two wire cables. Control wires of 
the rudder flaps or elevators run through the fin. The 
rudder is 1.40 meters high by .80 meters wide. 

The data -given out concerning the motor is as follows : 
" Motor: Hiero Flugmotor, Osterr; Ind. Werke Wars- 
chalowski, Eissler & Co.; A-G 6 cylinders; type HN1096. 
It develops 218 h.p. at 1400 revolutions per minute. 
Weight 314 kilograms. It is equipped with Bosch mag- 
netos and small starting magnetos. Propeller: 200 
h.p.h. Hiero 6 cylinders; diameter, 2.72 meters; pitch, 
2.25-2.40." 




Sketch showing the Austrian-Ago Sea-Pursuit Biplane " A-25 ' 
in flight 



SINCI.K MOTOKKI) A KU< >1M . A \ I - 




l.olui.-r l-'ljinjr Moat lc:t\ inp for a flight. Steel tiil.irij: plai ~ ,ui ii.i|x.rlaiil part in Hi. .oust ruction of this machine 

The Lohner Flying Boat 



This is an enlarged machine of the Lohnrr type, retain- 
ing tin- \' which is typical of the Lohner aeroplanes. 
There .in- six steel struts on either side and, two by two, 
.ire connected in transverse pl.-ines with steel tubes of 
Hi mm. outside diameter. The distance between two 
struts in the direction of the brace is 1.30 meters, and in 
the direction of Ihe spar 2.17 meters. 

General Dimensions 

Sp.m, upper plane 9.70 meters 

Sp.ni. lower plane 7.3) mrtrrs 

< hcinl. upper pi. me 2.70 meter* 

< linril, lower pliinr 2.M mrtrrs 

Mull. iii.-i\iiiiiiiii length li.iO mrtrrs 

Hiniili carrying capacity 400 kg. 

Motor, \n-tro Dataller soo h.p. 

Iii form the ailerons .in- tr.-ipcxoidal, like that of the 
It.-ili in I.olmcr machines. Length of ailerons, .S.17 me- 

mi an width. .!>() meters. 
Dinii iiMons of the empennage or tail group: Length 



of horizontal .stabilizer or tail-plane, 4.74 meters; width, 
ni-tiTs. Length of tail-flaps or elevators, 4.71 me 
ters; width, O.87 meters. The vertical rudder differs 
from that of the old 1 ohm r machines in that there is 
small balancing area forward of the pivot. 

The principal dimensions of the hull are: Maximum 
width, 1.50 meters; maximum length, li.SO meters; maxi- 
mum height. l.iO meters; step, .25 meters. 

The body has two seats side by side and one in front, 
upon which is mounted a machine-gun arranged to be 
movable and fired in any direction. Beside the pilot, next 
to tin- observer, there is also a machine-gun arranged on 
a movable tube inside the casing. The outside tube is 
the only additional piece the machine contains. 

The turret is armored. No bomb-dropping d< 
have been located. There are two vertical pieces of 
wood, with a circular profile notch fastened to the floats 
under the wings. It may be that these are used to drop 
large bombs, but no discovery li i* been made which would 




The winn float used on the " K-301," an Austrian S-seatrr flying boat of the l-ohnrr typr 



250 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




A close up view of a German flying 
boat, showing some new features of 
construction. Steel tubing is used 
extensively. The wing top floats are 
also of unusual design 



show how they are secured in them. Several hooks for 
small bombs were found. 

The lateral or wing-floats, instead of being hemispher- 
ical in shape, have a bow with good streamlines, which 
plow on the water surface like the prow of a ship. The 



accompanying drawing shows their general outlines. Each 
is 88 cm. wide and 181 cm. long. 

The engine, an Austro-Daimler, lias 12 cylinders a 
ranged in a V. It is rated at 300 h.p. 






CIIAl'TKK IV 



AEROPLANE AND SEAPLANE ENGINEERING 

Bv < OMMANUEK H. ('. UK inn s I > \ 



Tin- problem confronting tin Navy was largely detcr- 
inilii-il ;it tin- time tin- I'nitcd States entered thr w:ir by 
tin fact tli:it tin operations uf tin- (iiTinari and Au-.tn.in 
Hi ets I, i.l lii i-ii riiliu-iil |iritn-i|i.-ill\ to minor ranis fnun 
tin- Heel bases ,-it Kill and I'ola. ami tin only real sea- 
going operations comprised the activity of subnmriin I, 

Tin- work uf tin- si-a|il:iin s. tlicrcforc. was prim mlv 
reduced to that uf cooperation with the fleet in reducing 
the submarine menace. This naturally led to the estab- 
lishment of coastal .stations in France. Italy. F.ngland. 
Scotland and Inland. In these operations it was pos-i 
blc to operate seaplanes from shore banes in practically 
every CMC, ami the development of work with the fleet 
U-c.-ime a minor consideration. 

-mi- of the seaplane bases, however, werr sufficiently 
clnse tu enemy territory to \w within raiding distance of 
enemy planes of both land and water tyjK's. and it Ix-canic 
necessary for the Navy to extend its activities to the use 
of land planes for the protection of seaplane bases, while 
naval aviators also participated in big bombing raids on 
(iiriimn and Austrian territory. 

I refer to these matters in this grncrnl way, not to de- 
scribe tin activities, but to show that in naval work both 
land and water planes were used, and why the Xavy prob- 
lem was in general restricted to opi ration from shore 
bases rather than operation from ships. Activities, how- 
ever, were not confined to shore bases in Kurope. Sta- 
tions were established on the Atlantic const, principally 
for the purpose of submarine patrol and for convoy work 
from the principal ports from whieh our troops and sup- 
plies were sent abroad. 

Type* of Planes Developed 

The work of seaplanes abroad was that of submarine 
patrol and convoy work, and this having been determined 
on. all efforts were made to obtain the most suitable 
seaplanes for the service. The principal work was done 
with two tv|N-s of seaplanes, namely, the IIS-v! tin- sin- 
notored plane develo|x-d from the IIS-1 and the 
H-lfi. a copy of the Knglish seaplane of the same type 
il> v eloped as a result of Commander 1'orte's cx|>cricnce 
with tin- original America and subsequent types devel- 
oped therefrom. Finally, the F-.'i-I. type was developed 
from F.nglish designs for manufacture in this country by 
the Naval Aircraft Factory at Philadelphia. The ||> 
and the H-lfi have proved well suited to the work re- 
quired, but the F-5-L did not enter production early 
enough to get into active service before the armistice was 
red. 

The Navy did not attempt to develop land plane types. 
but accepted and used those which had been developed 

2.-. I 



nnd produced for tin Army, adopting for this purposi 
iirlish llandley-Page. the Italian Caproni. and the 
Army Dll I and DM 

In order that pilots should be trained for this s. r\ n 
it was necessary to adopt training planes, and for this 
purpose the \avy developed and used the Curtiss \ 
the H ti nnd the |{ :i. the Aeromarine and Hoeing sea- 
planes, and the F-boat. and also i \perimeiiti d with n 
number of miscellaneous types, such as the (iiiome scouts 
both biplane and triplanc of Curtiss and Thomas man- 
ufacture and the (iallaudet \)-.'>. The most successful 
of these training planes was the N-!i, particularly after 
the original float had Ix-en modified and Inter on after 
the substitution of the Hispano 13O-li.p. engine for the 
O.XX loo-h.p. engine. This plane was a biplane tractor 
with a single center float, having wing tip balancing floats. 
It was remarkably strong and could perform practically 
all sorts of maneuvers. Although in training work it was 
frequently wrecked, then- were remarkably few deaths 
resulting. This I attribute to its moderate s|>ccd. great 
strength of construction and tractor arrangement, which 
made it suitable for training purposes. 

As soon as it was determined that seaplanes of the 
flying-boat type were to IM- used in service it became nee 
essary to provide preliminary training in a type of sea- 
plane which more nearly represented the conditions of 
operation of the big boats. For this purpose the F-boat 
originally developed by Curtiss for sporting and for naval 
use was modified and adapted to instruction purposes. 

I shall later on describe and illustrate the principal 
types referred to. 

So far as the aerodynamical and mechanical features 
of construction are concerned, seaplanes differ very little 
from airplanes, the principal difference being the use of 
the landing gear suited to operation from the surface 
of the water instead of from the land. The proportions 
are. naturally, somewhat different, and the performance 
is different, primarily, because of the great inertia due 
to the increased weight involved in the seaplane construc- 
tion. But bearing this in mind, the details of construc- 
tion of seaplanes are substantially the same as those used 
in airplanes. 

Factors Affecting Performance 

It will now be of interest to consider the principal 
factors which affect performance, ns it is necessary to 
understand these completely to develop a design which 
shall perform according to the requirements of tin service 
intended. For the purpose of illust rating the factors 
involved I have prepared a set of performance curves, 
which I believe will give a clear insight into this phase 



252 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



of the problem. The complete calculation of the curves 
shown is given in the Appendix, together with the formu- 
las involved in the computations. 

The performance in power flight is determined by t 
horsepower required and the horsepower available, and, 
of course, the latter must always exceed the former ( 
power flight is not attainable. 

In determining the powei required there are two prin- 
cipal factors involved. The first factor is that of the 
horsepower required to propel the planes with their load 
in flight. This horsepower I term the plane's e.h.p. 
determine it, it is necessary to know the form and dis 
position of the wing surfaces used, as well as the aero- 
dynamic characteristics of the wing section employed 
The lifting power of the wing depends. on the area and 
the square of the speed of advance, and its resistance 
is also in proportion to the area and the square of the 
speed of advance, the speed of advance being the speed 
relative to the air itself and not the speed over the 
ground. 

The lift of an airplane surface and its resistance to 
advance are determined by the lift and drift factors, 
which vary with the type of section used and also with 
the 'angle of attack at which the surface is presented 
to the relative stream of air. It has been found by ex- 
periment that these factors are influenced by the propor- 
tion and arrangement of the surfaces, the best results 
being attained with what is known as the monoplane 
surface. 

Performance is improved by increasing the dimension 
of the wings in the lateral sense, over that of the fore- 
and-aft dimension. The ratio of these two dimensions 
is called the aspect ratio. As the aspect ratio is in- 
creased, it is found that the efficiency is improved indefi- 
nitely. But after an aspect ratio of 8 or 10 is attained 
the improvement in efficiency becomes less and less, and, 
practically, is not worth going after, because the dimen- 
sions become unwieldy and the gain in lifting power and 
efficiency may be more than wiped out, due to the in- 
creased weight and resistance of the structure required 
in employing it. It is largely on account of this diffi- 
culty that the biplane and the triplane have been used 
where large lifting power is required, even though in 
the latter cases the efficiency of the surfaces is reduced 
because of interference of the air flow, which is found to 
depend upon the gap ratio. By this is meant the ratio of 
the distance between superposed planes to the chord 
length, or fore-and-aft dimension of the wings. 

Where the leading edge of the upper plane is forward 
of the leading edge of the lower plane the efficiency is 
improved over that where one plane is immediately above 
the other, and conversely. This arrangement is referred 
to as stagger and the condition of positive stagger, that 
is, with the upper wing forward of the lower wing, is 
generally adopted with the view of improving efficiency. 
There are limits to its usefulness because of the obliquity 
of the trussing involved. 

Stagger may be adopted for various reasons, such as 
correcting the balance of an airplane in which the actual 
location of the center of gravity does not conform to that 
originally contemplated, or in order to improve the view 
of the pilot or observer, particularly if the latter is also 
a gunner. 



The efficiency is improved if the upper plane has a 
greater lateral dimension than the lower plane. This dis- 
position is known as overhang. There are limits to the 
extent to which this can be employed, on account of the 
structural difficulties involved. 

In the normal type of construction, the front and rear 
edges of the wings are parallel, although it is found that 
tapering the wings to a smaller fore-and-aft dimension 
at the wing tip improves efficiency. This arrangement is 
not satisfactory from a manufacturing point of view, as 
it involves different sized ribs at every station in the 
wings. All the above considerations have to be taken 
into account in determining the form and proportion of 
the wing surfaces. 

Another factor is very important, that is the travel 
of the center of pressure on the wing surfaces. It is 
found that where wings have a cambered surface which 
is usual in airplane construction because of the superior 
lifting power the movement of the center of pressure 
is such as to cause longitudinal instability. Various 
devices have to be employed to overcome this. The most 
satisfactory and usual method is to employ an auxilliary 
surface at the tail of the airplane called the horizontal 
stabilizer, and the best conditions for stability are found 
when this rear surface has a smaller angle of attack 
than the wing surfaces themselves. 

This difference of angle between the wings and tin- 
horizontal stabilizer is termed " longitudinal dihedral." 
The stiffness or steadiness of an airplane in flight de- 
pends on the area, proportion, section and angle of tin- 
rear surface. Where great stift'ness is desired, this rear 
surface may even assume the proportions of a second set 
of lifting surfaces which may be of monoplane or biplane 
arrangement, usually of smaller dimensions than the main 



400 

300 
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100 

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70 
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2 3 4 5 6 7 8 9 10 
Typical Motor Characteristic and Propeller Efficiency ("urv< 



.\KK01M..\\K AM) SEAPLANE K. Mil \KKKI\c. 



planes. Where the rear surfaces are increased to ncarlv 
tin- proportions of tin- forward surfaces, the tnndciu 
biplane arrangement is approached. 

For military purposes ami for combating rough air 
conditions it is foiiml ilrsjralili- to lia\r initial loiigitudi 
ii ii stability, lint it is undesirable to have tins in , hiijli 
decree on a military plain- in wliicli steadiness mav I* 
essential to tin- propi-r operation of a gun or of a luimli 
dropping device. If (In r. ar surface were completely 
ti\l in nil! i, in In the forward surface it would be possi- 
l>lr to proceed in liori/ontal flight at our definite 
only for tin- load carried, and ascending or desi ending 
could he accomplished only by increasing or di --re-ism ; 
the power, or 1>\ de, Teasing or in. Teasing (he Jnad. These 
methods of eontrol are not sufficient lv accurate or active, 
and it is nmeh more satisfactory to use additional sur- 
known a> eh -valors, appended to the rear margin of 
the hori/.ontal stal ili/.cr. which by modifying the 
of the stabilizer make it possible to proceed in horizontal 
flight at any speed from the minimum to the maximum 
Ihiii;; speid. or to i-anse the plane to rise or descend. In 

iirpiains. in order to get the maximum of r 
vcring ahility. the hori/.ontal stabilizer is reduced to a 
\rry small area: or. e\eii. in some cases, is completely 

d with, all being merged in the elevator. 
In the original Wright machine lateral balance was 
maintain. -d hy warping the wings, but this ir.'!:cd i 
unfavorable to strength in Inrp- structures. ai:d t.'ie use 
of ailerons for this purpose I. as n w h.-comc ; :i--rnl. 

In flight, airplanes are not always operatic! so that 
the trajectory conforms to the axis of the airp! -lie, par- 
ticularly when turning or when encountering side g :sts, 
As a consequence, unless what is known as the keel 
siiriace of the airplane is distributed equally above and 
In-low tin center of gravity, there is a tendency for the 
airplane to roll one way or the other, depending upon the 
location of the center of gravity relative to tlie center of 
lateral pn ssiire. To compensate for this cti'cct. or to 
provide lateral stiffness under such conditions, it is usual 
tn provide a moderate amount of what is known as lateral 
dihedral: that is. the winir, tips are higher than the center 
iiortion of the wings; or else skid tins are placed i:n:;: 
lintch under or above tin- upper wings. These in gen- 
ral have the same effect as lateral dihedral. Hy modify- 
ing this arrangement the amount of lateral stability 
can be controlled to any desired degree. Again for mili- 
irv purposes it is desirable to have initial lateral sta- 
lility. but not to such a degree as to interfere with con- 
rol! ability of lateral balance. 

Directional stability is also affected by the lo.-ati-n of 
he center of side pressure, depending upon its location 
fore-and-aft of tile center of gravity. It is essential for 
!y (light that the center of lateral pressure at small 
ngles of skew should not pass forward of the center 
>f gravity. To accomplish this it is usually necessary to 
nstall a vertical stabilizer at the tail of the airplane. It 
s again desirable to have initial directional stability. 
\nd again, in a military plane, it is undesirable to have 
his to such a degree as to interfere with control of 
lirection. As the airplane is symmetrical relative to the 
vertical fore-and-aft plane, it is unnecessary to provide 
my equivalent of the dihedral effect, and it is only n-ees- 
ary to append a rudder to the vertical stabiliser in order 



10 JO M 40 M 80 70 M 00 100 




10 20 30 tO 80 00 TO HO W 100 110 I'M 130 110 
I lorsrpower Curves of Ihp KAKtf Kiplnnr 

to control direction. In some planes, where extreme ma- 
u< uveral ility is desired. Uie rudder itself, in its neutral 
position, performs the functions of a vertical stabilizer 
as well na that of a rudder, and no vertical fixed surface 

is used. 

Location of Powerplant and Crew 

1 1 iv in:: given due consideration to the influence of the 
proportion, arrangement anil dispositio-i of the main siip- 
porting and control surfaces, it is m-x' n -n ss.-.rv to eon 
sidcr the service intended and the location of (he power- 
plant and the crew. The possible arrangements arc al- 
most infinite, but in general it is desirable to locate the 
pilot centrally where he will have a proper view to enable 
him to handle the airplane to the greatest advantage, and 
this is particularly necessary in the combat plane. It is 
also essential that the gunner shall have an large and 
unobstructed a view as practicable, and that with the gun 
positions selected he shall IK- able to cover his are of 
fire and as much of the surrounding sphere as is prac- 
ticable, in order that there shall Ix- no dead spots from 
which the enemy may approach without his being able 
to return the fire. This sometimes requires that the pilot 
himself sh ill be able to operate guns firing dead-ahead, 
or that additional gunners shall Ix- placed so that they 
can cover area of fire not possible for the others to 

cover. 

In bombing planes and. in particular, in night bombing 

ones, this requirement is of less importance, and the 
requirement that the lx>mh dropper shall have a pro|XT 
view for the operation of the bomb sights become* of 
prime iin|tortancc. 

In airplanes di -signed for long-distance flights or for 



254 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



bombing, it becomes necessary to have great power avail- 
able, and this requirement has led to the adoption of mul- 
tiple unit powerplants. Two, three, and as many as five 
powerplants have been successfully used for this pur- 
pose. The multiple-engine plane has the advantage that 
in case of damage to one powerplant it is usually possible 
to continue flight with those remaining; or, if still too 
heavily loaded to accomplish this, it is possible to glide 
for a long distance and thereby select a more favorable 
landing place, and often to avoid landing on enemy terri- 
tory. 

All these and many other considerations enter into the 
disposition and arrangement of the powerplant and fuse- 
lages, and these arrangements themselves have an influ- 
ence on the performance of the wing surfaces because of 
interferences involved. 

By winging out the powerplants a more favorable load 
distribution is imposed on the airplane structure and ad- 
vantage is taken of this feature in designing the wing 
trussing. The effects of interferences and of the dispo- 
sition and proportion of the wings or bodies and auxil- 
iary surfaces are so complex that unless data are already 
available from similar designs, it is very desirable that 
the resistance and lifting power of the complete design 
should be determined from wind-tunnel tests of a model 
carefully constructed to scale in every detail. Such model 
test is usually deferred until the design has approached 
some definite form after preliminary estimates have shown 
that it is capable of approaching the performance desired. 

Form and Proportion of Wings 

In preliminary estimates the influence of the form and 
proportion of the wings is carefully estimated, and from 
these estimates a fairly accurate approximation of the 
horsepower required for the planes is derived. To arrive 
at the total horsepower required, it is next necessary to 
consider the horsepower required to overcome the head 
resistance. In order to do so, it is necessary to have 
accurate knowledge of the resistance of all elements of 
the airplane structure exclusive of the wings, which are 
exposed to the action of the wind in flight. 

To reduce the resistance of these elements to a mini- 
mum, streamline forms are adopted wherever practicable, 
and even the truss wiring is made up of streamline form; 
or, if this is not found practicable these wires are cov- 
ered with false streamline covers of wood or metal. It 
is found that the reduction in resistance more than com- 
pensates for the additional weight involved in applying 
these false covers. 

The resistance of the fuselages, radiators, engines, tail 
control surfaces, elevator rudder, aileron horns and all 
other elements is computed in detail, and account is 
also taken of the obliquity of these elements to the flow 
of the air. Such obliquity is found to exert an important 
influence on their action. For preliminary estimates, it 
is customary to determine the resistance of these elements 
for the position assumed by them at some speed inter- 
mediate to the low flying speed and to the high speed 
attainable with full power, and then to assume that the 
resistance of these elements is proportional to the square 
of the speed for speeds above and below the intermediate 
speeds selected. This is most handily done by assuming 



that the resistance of these elements is represented by a 
flat surface exposed normal to the wind, which would 
have the same resistance as the aggregate of these ele- 
ments. This supposititious surface is what is referred 
to when we speak of the " surface of equivalent head re- 
sistance." In the example which I have chosen to illus- 
trate, " the equivalent head resistance " is assumed to be 
20 sq. ft., and the horsepower required to drive this head 
resistance through the air is indicated on the curve de- 
noted head resistance horsepower. By compounding the 
ordinates of this curve with the ordinates of the plane's 
e.h.p. curve we derive the total e.h.p. required curve. 

We have next to determine the total brake horsepower 
available in order to determine the performance of the 
airplane. To determine this curve, we must first know 
the full-throttle characteristic of the engines to be used. 
This characteristic is indicated in the example showing 
the brake horsepower available at different speeds. 

The next thing to be determined, and the one having 
a most important influence on the performance of the 




T|T Tp 1 1 1 1 1 

ttltolMHtMIM 

Chart for Determining the Dimensions of Propellers 

airplane, is the propeller characteristic. To date the 
progress in propeller design has been far from satis- 
factory, and although good results have been obtained, 
the best results possible have seldom been approached. In 
the selection of the propeller, one of the first considera- 
tions is to determine what feature of performance is 
most important, for it is necessary to select the proper 
dimensions with a view to gaining the best results for 
the service intended. For instance, if high speed is of 
greatest importance, the propeller to be selected will differ 
materially from that which would be required if great 
climbing power is desired, because the greatest climbing 
power will be attained at a speed much lower than the 
maximum rate. Or, it may be a question of selecting! 
a propeller which will give the greatest efficiency at cruis- 
ing speed, and this propeller will usually differ from that 
selected in either of the preceding cases. In some case* 
it may be desirable to select a propeller which will give 
the best all-round performance rather than for a par- 
ticular condition. 

In seaplane work a problem arises which is not found 
in the land airplanes. This problem is that of obtaining 



AI.K01M.AM. AM) SKAIM.ANK K.\<; I NKI .]{ 1 \ i . 



tlir crc.-itcst reserve of |mi r to n\ i rcoiue the resistance 
of tin- Hn.-it system, because it is desirable to have the 
_TC at. st possible reserve ti> accelerate rapidly on the 
watrr. so that the ^i-t away may In- made in rough water 
with the greatest possible rapidity, thereby reducing the 
uinislimciit which tin- sraplan.- suffers under siu-li <-on 
litions. I-'or a licavily loaded seaplane this consideration 
nay IK- of \ ital importance. 

Efficiency of the Propeller 

It must he understood that the efficiency of an airplane 

propeller is absolutely depeiident upon its speed of ad- 

vanee through the air. as is also the power which the 

impeller alisorhs in flight, the result being that CM-II 

liou^li the full throttle is used the engine cannot make 

its full revolutions until a good flying speed is attain., I. 

with the consequence that full power of the motor cannot 

:ie realized until flying speed is attained. 

The efficiency of a propeller is dependent upon n func- 
tion of the velocity and the number of revolutions and 
tin diameter of the propeller represented by the frac- 

y 
ion - The efficiency, the torque and the thrust, the 

lorscpower absorbed and the horsepower delivered are 
'unctions of this quantity, in which velocity, the number 
>f revolutions and the diameter must be expressed in 
lie same units. 

'flu influence of this factor is indicated on the pro- 
icller ellicii in -\ curve based on the values of the fraction 

. When this fraction equals 0.2 the efficiency of the 

ND 

impeller indicated in the example is only 37.5 per cent. 
The maximum efficiency is attained when the value of 
his fraction is 0.59. the maximum efficiency indicated 
n this case being 73.2 per cent. 

In the example chosen I have used a Durand propeller 
the characteristics of which have been determined 
>v wind tunnel tests, as reported in report No. H of the 
.irocei diiins of the National Advisory Committee for 
Veroimutics 101-1. 

To derive the dimensions for this propeller I have 
issuiued that it is desired to attain the best results at 80 
niles per hr. with a I.ilk-rty engine operating at 1600 
.p.m. and developing 380 b.h.p.. as shown by the motor 
haractcristic. In Professor Durand's report he has 
idopted KifTel's logarithmetic chart, and I shall now indi- 
ate how the diameter of the propeller is determined. 

On the chart at a speed of 80 miles per hr. erect 
in ordinate equal to 380 h.p. taken from the scale 
>n the left side of the chart. From the top of this 
irdinati next draw an oblique line parallel to the line 
ndicatini; the speed, and draw this line of such a length 
nd in such a direction ns to represent IfiOO r.p.m. on the 
scale starting with the origin at 12OO r.p.m. From 
:he extremity of this line m \t draw a line parallel to the 
ting the diameter scale, and taking the distance 
: rom this point to its intersection with the propeller 
haracteristic for the propeller No. N we find that this 
in.- intersects at the point (). Transferring the length 
nf this line to tin diameter scale and measuring in the 
firection in which it is necessary to draw this line to 
anake it intersect with the propeller's characteristic, we 



find that the proper dinmeter to use is (1. 4 ft., in.li, ,lin- 
an efficiency of <;.' ).. r nut Hy the us, nf tills ingenious 
chart it is possible to select a pmp< r diameter for a 
given set ul conditions by a simple graphical solution. 

The diameter now Ik-ing determined, it is next neces- 
sary to determine the perform. nice of the combined 
engine and propeller, and this is done as follows: On i 
transparent sheet of paper or tracing cloth a base 
line is drawn and. from any convenient point on this 
line, another is now drawn parallel to the scale of pro 
peller diameters and a distance is laid off representing 
the diameter of the propeller on that scale. I' mm the 
extremity of this line a new line is drawn parallel to the 




Chart for Determining the Performance of a IJIierty Knjrfne 
am) a Durand No. H Pro|>rllrr 

scale of revolutions per minute, and on this line is indi- 
cated the revolutions per minute of the powerplant. 
using the scale of r.p.m. for this purpose. From each 
point representing the different revolutions vertical or 
din iles arc now drawn, representing, according to tin- 
horsepower scale, the brake horsepower dc\eln|M-d by the 
engine at these revolutions, and through the points so 
determined a motor b.h.p. curve is drawn. 

Ni\t place this diagram on top of the logarithmetic 
diagram of the propeller, placing the origin on the base 
IIIK / on the base line of the logarithinetie diagram 
with the point .1 at the s|x-ed at which it is desired to 
determine the brake horsepower available. The pro 
peller efficiency, and from the latter the e.h.p. available, 
can now Ik- determined. 

This construction is based on the fact that the hone- 
power absorbed by the propeller and the horsepower 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



delivered by the engine must agree. Thus, for example, 
placing the point A at a speed of 30 miles per hr. it is 
found that the brake horsepower curve of the diagram 
intersects the propeller characteristic and the engine 
characteristic at a point B, indicating that the engine 
will make 1500 r.p.m. and develop 355 b.h.p. at this speed 
of advance. 

By drawing a vertical line through this point of inter- 
section of the two curves to the dotted characteristic of 
the same propeller, the e.h.p. developed by the propeller 
may be determined. This can also be determined by 
measuring the distance on the vertical line between the 
full line and dotted line representing the propeller char- 
acteristics. By transferring the length of this line to 
the scale for efficiency, the propeller efficiency can be 
determined. 

In this manner the brake horsepower available and the 
e.h.p. available have been determined and are shown on 
the horsepower curves on page 3. It will be seen that at 
30 miles per hr. the engine can only turn the propeller at 
1500 r.p.m., developing 555 b.h.p. Also, that at this 
speed the efficiency is only 35 per cent and only 12-1 e.h.p. 
is available, although the engine is developing 355 b.h.p. 

Determining Plane Performance 

Having now determined the e.h.p. available, we are 
ready to determine the performance of the aeroplane. It 
will be noted that the lowest speed indicated in power 
flight is 58.5 miles per hr. Thus these two points of per- 
formance are determined. 

The climbing power of the aeroplane with full power 
is determined by taking the difference of e.h.p. required 
and e.h.p. available at the particular speed at which the 
airplane is flown in the climb. This difference is greatest 
at the speed of 73 miles per hr. The climb is determined 
from the reserve e.h.p. available, which in this case is 
76. Multiplying this e.h.p. by 33,000 and dividing by the 
weight of the airplane, assumed in the example to be 
6500 lb., it is found that the initial climb should be 386 
ft. per min. 

Further inspection of the curves shows that the mini- 
mum horsepower is required at a speed of 62 miles per 
hr. -It is at this speed that the airplanes should be 
flown to get the greatest endurance. If, however, it is 
desired to get the greatest range, the most favorable 
speed will be indicated by drawing a tangent from the 
origin to the e.h.p. required curve, as at this point the 
most favorable ratio is attained between velocity and 
horsepower required. 

In the example this speed is found to be higher than 
the speed for minimum power and is about 73 miles per 
hr. It will b; noted that the tangent to the curve sub- 
stantially conforms to the curve over the range of speed 
from 70 to 76 miles per hr. If the endeavor is being 
made to cover the greatest possible distance, it would 
be desirable to select the higher of these two speeds, for 
the reason that at the higher speed the controls would be 
more effective; the flight would be steadier and would be 
accomplished in a shorter time. 

As the aeroplane proceeds its weight will be reduced 
because of the consumption of fuel, and with a plane 
of heavy carrying capacity this reduction of fuel at the 



end of a long flight will appreciably reduce the load and 
thereby decrease the horsepower required for flight. 

In the example chosen, I have indicated the horsepower 
required when all the fuel is used up, assuming a weight 
at this time of 1500 lb. In this condition the most 
efficient speed will again be indicated by a tangent to 
the origin, and in the example this speed is appreciably 
lower than that indicated for the full load condition, 
being anywhere from 55 to 60 miles per hr. At inter- 
mediate stages intermediate speeds will be found the 
best for the greatest range. This, therefore, indicates 
that in planning a long-distance flight due account should 
be given to this effect, as the radius of flight will be ap- 
preciably increased if proper account is taken of the in- 
fluence of change in weight. To be exact, the tangent 
should not be drawn to the e.h.p. required curve, but to 
a set of curves which can be derived from these curves 
indicating the fuel consumption at different speeds and 
at different loads. The determination of the fuel con- 
sumption curves is a simple matter, but it would take 
more time and space than I consider it desirable to give 
in this paper. I can state, however, that the favorable 
speeds for long-distance cruising are not appreciably 
affected by using these fuel consumption curves in pref- 
erence to the e.h.p. required curves. 

The computations made in deriving the curves showr 
have been based on the Liberty engine, using straight 
drive. If it were possible to have available the same 
power with the geared-down propeller, it would be pos- 
sible to greatly improve the propeller efficiency anc 
thereby to improve the performance of the airplane indi 
cated in the example. It is unfortunate that the geared 
down engine is not available for general use, as the per 
formance of practically every plane I know of usinj 
tin's engine in our country would be materially improve( 

y 
bv its use. An inspection of the - efficiency plot wil 



make this clear. I also consider it unfortunate tha 
in the development of the geared-down Liberty engine 
which have been produced, advantage has not been take] 
of the possibility of locating the propeller more centrall; 
in relation to the engine group, because of the advantage 
which would be gained in streamlining. This engine i 
extremely awkward to streamline in its present form. 

Design of Seaplane Floats 

I will now proceed to the consideration of some o 
the elements of design of seaplane floats. The require 
ments of seaplane floats, because of the nature of thei 
use, are necessarily conflicting, and the best that can b 
done is to make a compromise, bearing these in mind. 

The first requirement of a float is that it shall be set 
worthy. This requires that the form shall be properl 
proportioned to provide good initial stability and 
reserve of buoyancy. This is necessary to obtain a re 
serve of stability, as the seaplane must float withoJ 
capsizing in a sea-way and in strong winds. This r 
quirement in itself conflicts with airworthiness ad 
lightness and with the adoption of the best streamliJ 
form, which otherwise would be, in general, a form sir 
ilar to a dirigible. It must be strong, but this natural! 
conflicts with lightness. It must also have good plal 



AKKOl'I.ANK AM) SKAIM.ANK KN( . I M .KM I \ i , 






nil qualities. .Hid tlii-. reipiirem.nl conflicts with str. un 
nc form. Airworthiness requires that it should have 
ir iiiiniiiiiini resistance and interfere ill tin- I 
hli- decree with the otlliT characlerist ics of the seaplane. 

In order to dcu-lop tin- best form of hull, tin Vi\\ 
)r]>;irtinriit began experinn ills .it tin- Washington nmili 1 
isin late in lull. These experiments wen initiated by 
apt. W. I. Chambers. I . S. V. with a \ ii -w to tin- 
si- of hydroplane IHadi-s. such as had been used li\ 
orlaiiini. anil to improving tin |)aninir <|imlitics of the 
ii-n existing types of floats. At that time the most sue 
iful float was that eonstriieted by (ileiin II. Curtiss. 
i\ iiiiT a simple l>o\ seel ion and a slid form profile. At 
le same time Burgess I,.,,] developril twin floats having 
single step, which had also pnn- -fid. 

One of the earliest experiments at tin- model liasin was 
i attempt to reduce the welted surface to a minimum by 
ic use of a semi-circular section in the form of a half- 
ilind.r whose ends were pointed like a projectile to 
diice the air and water resistance. It was fortunate 
lat this model was tried ainonir the first, for its trials 

once showed up a factor which later was discovered 
) lie of the greatest importance, this factor bcinir suction, 
n- to downward curxcd surfaces when exposed to tin' 
intact of water at high speeds. It was nt once realized 
lat in the test of the floats due allowance sho lid br 
ade to repns.nl tin change in load carried by the float 
s the speed of the seaplane increased and the lift of 
it- wmijs hccamc an important factor, and all runs at 
ie model I'asin had In'en made taking account of this and 
tcrminini; for each particular speed the " corresponding; 
splaccmcnt " of the float. This was originally done by 
mnterwcighting the float so that the weight resting on 
< water represented that which would he the case fak- 
ir into account the auxiliary lifting power of the wings, 
i the latest form of apparatus for testing at tile basin 
lis compensation is automatically made by the use of 
i inclined vane submerged in the model basin, which, 
v mi-ails of a system of pulleys, exerts a lifting power 
Inch is proportional to the lifting power of the wiims 
: the speed at which the test is run. 

In the tests with the semi-cylindrical model above re- 
rred to. it was found, as anticipated, that the resistance 
t low and moderate spuds was less than that cxperi- 
>ith other models, lint as one half of the speed for 
away was approached, and therefore the float car- 
ed only thr. i quarters of the original load, it was found 
mt the resistance of this model instead of decreasing. 
icreased: and that the model, instead of pinning, as 
as expected, settled into the water and. finally, at the 
et-away speed, with no weight being carried by the float 
ut the float just in contact with the water, the influence 
ion was so great that this model, instead of skim- 
ing the surface, proceeded to envelope itself in water 
a drawn down so sharply by suction that its deck 
M flush with the surface of the water in the tank and 
h.ets of spray were lifted clear of the surface 
f the mod-. 1 ! basin. 

A the work progressed the models of every known 
uccessful type of float were tried in the model basin. 
nd data were collected as to the performance of these 
lodclv At the same time many exjx-rimental model* 



were tried, and when these showid imprint im ir 
existing types, full si/id floats , r. eonstriieted and tried 
out in actual flight. I' mm these trials it was found that 
tin i oiiditions indie.it> d in tin model li.isin wen duplicated 
ill practice with full size, and it uas set n that the model 
I asin tests fori! ins of predicting the pi rtorui un 

of full sl/.ei| |(. 

The steps of the Hurgess floats were ventilati d. and 
an investigation of this feature showed the value < 
tilation for the step type floats then in use. 

All sorts of bow forms were tried and were shown to 
r\ little influence on performance. The use of 
one. two. three and four steps wns tried, and the indn i 
dons were that there \\.-is little, if any. advantage to IM- 
gained by the use of more than two. 

The introduction of the V bottom showed promise of 
improienn nt. but it was early found that a V-lftittom 
at the how was invariably associated with large i|iianti- 
: spray which would flow over the planes, and also. 
a cross wind would make the navigation of the senpl-ines 
very uncomfortable. It was found by making the lines 
hollow at the bow that this spray could he held down close 
to the wait r. and ill some later designs this hollowinss 
was also introduced nt the step, apparently with tune 
tieial results. After much experimenting it finally IM- 
.-.ime apparent that the best form of hull wns that em 
lodying the single veiitilnted step, in which the after 
bottom rose at an angle of approximately H deg. to the 
bottom just forward of the step. The reasons for this 
ore about as follows: With this type of float sufficient buoy- 
ancy can IM- provided abaft the step to eliminate the in c. s 
sity of tail floats for stability. It was also found that by 
ventilating the step the water flowing under the forward 
bottom flowed over the step in the form of an im.rt.d 
waterfall and that the contact of this inverted stri am moved 
further aft as the speed increased and i: in rilh paused 




102030406060708090 100110120130140 
Seaplane hortepower currm afloat and flylnit. 



258 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



clear of the tail of the float just before planing was at- 
tained. At this point maximum resistance was encount- 
ered. After this point was passed the float proceeded to 
plane on the forward step, and because of the raised 
position of the tail of the float, it was then possible to vary 
the trim of the plane and change the angle of attack with- 
out again bringing the tail of the float into the water. 
Then progressively as the speed increased to flying speed 
the planing power of the portion forward of the step in- 
creased rapidly and the amount of wetted surface exposed 
to the action of the water was rapidly reduced, and the 
resistance of the float decreased, until finally at the get 
away the water resistance of the float was eliminated. 

The best results are obtained where the bottom of the 
float just forward of the step is substantially parallel to 
the axis of the seaplane. This portion of the bottom 
should have no curvature for a distance of several feet 
forward of the step. 

Attempts were made to curve up the portion abaft the 
step with a view to producing a better streamline form 
for the hull, but this curvature was invariably found to 
produce suction, retard planing, and in many cases to 
augment the resistance of the float to such a degree as to 
require an excessive reserve of horsepower in order to 
get away. There was one case where a flying boat was 
built with very moderate curvature abaft the step, but 
on account of this curvature in the tail was unable to 
leave the water with a single passenger. Even though it 
could get up to a speed where the step itself was clear 
of the water, the tail would still drag and could not be 
drawn out of the water. By slightly modifying the tail 
of the float so that the lines abaft the step were straight, 
this same flying boat with the same powerplant was able 
to get off the water with a pilot and passenger. 

One of the earliest floats tried at the model basin and 
built in full size was a twin float having a sharp V-bottom. 
The lines of this float conformed to the lines of a success- 
ful gunboat, and it was very pretty and clean in its action, 
but due to the influence of the curvature of the buttock 
lines at the stern, suction was present in this model and 
an airplane fitted with these floats, although able to get 
away with a pilot, was unable to get away with a pilot 
and passenger, there being insufficient reserve power to 
get over the hump. 

Until very recently it was considered that so many 
inches of beam were required for every 100 Ib. of weight 
carried by the float in order to attain planing, and this 
criterion has led to the adoption of the great beam found 
in the F-5 and H-16 and HS-2 models. But experiments 
with floats suited to carry 1000 Ib. each indicated that 
this model was remarkably satisfactory. The attempt 
was therefore made to enlarge this model in geometrical 
proportion to a 2000-lb. float, and the model basin results 
indicated that this could be satisfactorily done. Another 
model was made of a 2000-lb. float and behaved satis- 
factorily. This same model was expanded to a 6000-lb. 
float, which behaved even better than the original. The 
lines of the N-9 float, which has proved successful in our 
training program, were developed from the original 
1000-lb. float, although this float had less beam than the 
original full-size float which was unsuccessful. As a re- 
sult of these trials, I now consider it to be conclusively 



established that once a satisfactory float is developed fol 
carrying a definite load under given conditions, the same 
design can be used for larger loads by merely expanding 
the original lines in the ratio of the cube root of the 
displacement ratios. 

In the design of the float for the NC-1 this principle 
was used and the model tested in the model basin, aH 
though only one-twelfth full size, gave data which indi- 
cated satisfactory performance. These data have been 
closely verified by the actual performance of the NC-lj 
though many designers were skeptical that this floaj 
could handle its load on so narrow a beam. This is nfl 
greater than that used in the F-5 ; the F-5 carries a load 
of only 13,000 as against over 22,000 Ib. carried bj| 
the NC-1. 

Attention is now invited to a series of curves showing 
the results of model basin tests on a number of different 
models. 

Results of Model Basin Tests Compared 
The dimensions of the' floats and the seaplanes thej 
represented were so different that to get a comparison 
it has been necessary to plot these results on non-diuieni 
sional scales. It will therefore be noted that the disj 
placement of the hull is plotted as a per cent of tha 
total displacement based on a per cent of the get-awal 
speed. The resistance of these floats is indicated by 9 



tAPERIMENTAL MODEL BASIN 

AIRPLANE FLOAT TESTS 
MODEL NO. FOR -NAME 

H-12 

20,55 AA.D. 

20SO H-l 

2<*1-A K-C-I 

2081-B 

2081-C 




30 40 50 60 70 

PER CENT OF GETAWAY SPEED 



Results of tests at model basin on a number of seaplane floats. 

plot of the ratio of the displacement to the resistance! 
also, based on the per cent of the get-away speed. 

Based on the plot of model No. 2022, which is that o$ 
a successful H-12 boat, I have plotted the resistance and 
the horsepower required to overcome this resistance for 
the sample seaplane, the horsepower curves of which I 
have already explained, and I shall return to those plots 
in a few minutes. Before doing so, however, I wish l<> 
invite your attention to the plots of models Nos. 2081-^ 
2081-B and 208 1-C. You will note that the resistanc 
of No. 2081-A was nearly one-quarter of the displace 
ment at 40 per cent of the get-away speed ; that th 
resistance of No. 2081-B was reduced to nearly one-fift 
of the displacement at about 47 per cent of the get-awajj 
speed, and the resistance of No. 208 1-C was between oiic- 
fifth and one-sixth of the displacement at about 52 pel 
cent of the get-away speed. Also, the displacement il 
the latter case is less than in the preceding cases. 



AKKOIM.ANK AM) SKAIM.ANK KMJ I \ KKI{ 1 \ ( . 



J.V.i 



Tills change was brought aliout as follows: The 
original form of float had two -I. ps. with curvature in 
Hi. nii.ldlr step and a rank tip-curvature in tin- rear step. 
So. -.'iiM 15 represents this model with tin- rear step 
straightened, anil No. -.'I IS I (' represents this Mnat with 
straight lines for tin- liottom ahaft the tirsl st, p. It will 
rraililr In- si-i-n th.it tin- first modification was an im- 
provriurnt oicr tin- original, ami tin- s.-conil ino<lifiratioii 
was a still greater improvement. Thrsr modi Is rcprc 
si-nt tin- model of the NC-I. and there is no doubt in my 
mind that if tin- original inodi-1 had heen iisi-d this sea- 
plane could not have pit oil' the water. Further, the 
influence lit the curved portion at the tail of the float 
would have been so great as to cause the machine to squat 
so liailly that the tail surfaces would have heen caught 
in thr stream of water rising from the tail of the float. 
Let us now return to the horsepower curves. It will 
he noted that the resistance of this seaplane float reaches 
a maximum at a speed of '<) miles per hr.. which speed 
corresponds to n point at which planing lie-ins, and 
there is a secondary hum)) at a speed of to miles 
per hr. The get-away speed is assumed as lix! miles j)er 
hr. The horsepower curve has been directly derived 
from the resistance of the float, and this horsepower must 
he compounded with that of the airplane progressing 
through the air. The horsepower required for this pur- 
pose is determined by taking the horsepower of the air- 
plane at ii-,' miles per hr.. which in this ease is 150 e.h.p., 
and noting that the horsepower for the wings and head 
resistance is proportional to the cube of the speed. We 
thus derive the curve of the total air e.h.p. required for 
the seaplani . which must he compounded with the horse- 
power required for the float, thus giving s a total 
horsepower curve for the seaplane for speeds below the 
get-away speed, that is. while still in the water. 

l-'rom an inspection of the horsepower curves, it will be 
set n that the maximum horsepower for the float is re- 
quired at a .speed of about ':! miles per hr., and that this, 
compounded with the horsepower due to air resistance, 
requires 88 h.p. at this speed. 

The horsepower for planing is very little exceeded by 
the horsepower available, so that it would take a rela- 
tively long time to pass through the planing condition; 
but. after this point is passed, the seaplane should accel- 
erate rapidly because the reserve of horsepower available 
rapidly increases up to the get-away speed. 

There is a secondary hump in the horsepower curve at 
60 miles per hr. just he fore the get away in attained, but 
this secondary hump is of little importance as there is 
an ample reserve of horsepower at this point. 

As a matter of interest, I have investigated the im- 
provement in performance which could bt expected if 
a geared-down engine were used, assuming a ratio of 0.6; 
that is. the propeller turning at 0.6 of the revolutions of 
the engine. With this gear ratio a propeller IS ft. in 
diameter is indicated. Such a propeller at a speed of 80 
miles IXT hr. would show an efficiency of 73 per cent as 
against 6W per cent for the -ft. diameter propeller. 
This gain of I per cent at HO miles per hr. would increase 
the climb by more than 1 1 per cent. It would have little 
effect on the speed, as the horsepower curve is very steep 
in this region. The improvement in efficiency at 20 miles 



per hr., although only 6 per cent would mean an met 

of -..'00 per cent in the r.s.rv, of horsepower to get over 
the hump in the horsepower curve at that speed. You 
will therefore see why in naval work the use of the 
geared down propeller oll'crs considerable advantage. 
The siilstitution of the gcared-down Liberty for the 
straight drive Liberty engines in th. I .1 changes the top 
speed of this seaplane from '.Ml to loo nnli s p, r hr. and 
makes the get away of this seaplane certain and rapid 
under all conditions, whereas the straight-drive propellers 
were only able to get this boat with great difficulty in a 
calm. 

The V- Bottom Versus the Flat 

I. \periments have recently heen made at the model basin 
on a series of models having different angles of V-bottom 
from the flat bottom up to a 20-deg. V, and it is found 
that from a resistance point of view there is very little 
difference in the performance of the four models tried. 
So far as any advantage is shown, the deep-angle V 
has slightly the l>est of the argument. From a service 
point of view the deep V-bottom has many advantages; 
among them its remarkable shock-absorbing properties 
in taking care of bad landings, or in getting away and 
landing on a rough sea. The V-bottom also permit- 
landing across the wind without serious retardation and 
without danger of capsizing sideways. This type of hull 
appears to absorb the shock by penetration and reduces 
the loads imposed on the bottom planking and on the 
framing supporting this. Due to this feature there is 
no need of carrying shock absorbers between the floats 
and the rest of the plane structure, and the lightest 
possible construction can Iw adopted. 

In the longitudinal system of support the inner ply 
of planking is run athwartship and thereby constitutes 
a continuous system of ribs. This system is further 
reinforced by the outer planking run 45 deg. to the keel, 
which also acts as a continuous system of ribs, and these 
two systems transmit the water pressure as a distributed 
loading to the longitudinal members, which do not have 
their strength robbed by a series of notches. The lon- 
gitudinals are arranged so that they collect the dis- 
tributed load and concentrate it at points of support in 
athwartship bulkheads and these bulkheads in turn dis 
tribute the load to the keel, to the chine stringers, and to 
the deck planking. The keel itself is usually associated 
with a center longitudinal truss. Through these mem- 
bers the load is finally distributed to struts or directly 
to the wing structure. 

On a large scale this system is adopted in the construc- 
tion of the hull of the NCI which, although it embodies 
other features than those necessary to support the bot- 
tom planking, weighs only 600 Ib. while it carries a 
load of -J-MI.IH Ib. This hull has demonstrated ample 
strength in landing on and getting off an 8-ft. cross sea 
in practically dead air, where the landing and get away 
were both made under the hardest conditions. 

A controversy has existed for years as to the merits 
of the single float as compared with the twin float, but. 
based on the experience of our Navy with examples oi 
both types, I believe that the central float with wing tip 
balancing floats is decidedly the better arrangement. In 



'260 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



the central float system the loads can be concentrated on 
the point of support, whereas in the twin-float system 
the loads are usually concentrated in the center of the 
span and the wing structure has to be utilized to gain 
the necessary stiffness and necessarily has to be made 
heavier. In the center-float type if a single propeller is 
used it is located above the float and protected from the 
water, whereas in the twin-float type such propeller neces- 
sarily swings over the gap between the floats, which 
subjects it to punishment by spray and broken water. 
In landing a twin-float seaplane, unless botli floats arrive 
at the same time, the second float invariably strikes 
harder than the first, being slammed down on the water. 



Due to the greater lateral stiffness of the twin-float sys- 
tem, when getting off rough water the seaplane is forced 
to conform in its attitude to the form of the surface 
and wracks and lurches violently sideways unless going 
directly across the crest of the sea. In maneuvering in 
the air, also, the separation of the twin floats adds con- 
siderably to the inertia about the longitudinal axis and 
makes the action of the ailerons less effective. With twin 
floats, when taxi-ing across a strong side wind the lee 
float must have at least 100 per cent reserve buoyancy 
and this leads to greater weight than is necessary witli 
the single center-float providing the same stability. 



Appendix 


V 


3 


Kill', 


The tables appended give the calculations for the per- 


10 

20 


1,000 
8,000 


O.Hi 
1.28 


formance curves of a seaplane with a biplane arrange- 


30 


27,000 


4.32 


ment of R. A. F. 6 wings and a head resistance of 20 


40 


64,000 


10.34 


sq. ft. In these calculations the following formulas were 


50 


125,000 


20.00 


usod : 


60 


216,000 


34.60 




70 


343,000 


55.00 




80 


572,000 


82.00 


K W TV 

T = W 4- -7-^ I'- = -r , EH~P - 


90 


729,000 


110.50 


/i 1\. S 375 


100 


1,000,000 


KiO.OO 




120 


1,728,000 


270.00 



W Weight in pounds 
T = Thrust in pounds 
V = Velocity in miles per hour 
8 = Wing surface in square feet 
*^. = Drift factor for biplane arrangement 
K U Lift factor for biplane arrangement 



EHP, 



WAV- T', AV 



% 



= 6500 l^ =M4g 













/W, 


\ / H 


^2 \ 








EHP 




(w. 


',) = I - 3 (ii 


rj = 1.73 


T KJS 


F* 


r TV 


Flanes 


- 


EPIli 


r, 


EIIP, V, 


1,030 0.301 


21,600 


147.0 151,300 


404.0 





404.0 


147.0 


234.0 122.5 


532 0.595 


10,900 


104.5 55,700 


148.5 


2 


148.5 


104.5 


86.0 87.0 


474 0.861 


7,550 


87.0 41,200 


110.0 


4 


110.0 


87.0 


68.5 72.5 


516 1.085 


5,990 


77.5 40,000 


106.7 


g 


106.7 


77.5 


61.5 64.5 


575 1.309 
618 1,512 


4,960 
4,300 


70.5 40,500 
65.7 40,600 


108.0 
108.2 


8 
10 


108.0 
108.2 


70.5 
65.7 


62.4 58.8 
62.5 54.8 


684 1.708 


3,800 


61.7 42,200 


112.2 


12 


112.2 


61.7 


65.0 51.5 


833 1,848 


3,520 


59.5 49,500 


132.0 


14 


132.0 


59.5 


76.3 49.6 


1,160 1.911 


3,400 


58.5 67,900 


181.0 


16 


181.0 


58.5 


104.6 48.8 


K SV3 
EIIP h = ^pp and is independent of the angle of attack. 


The float 
and having 


EHP for an H-12 seaplane weighing 6500 Ib. 
a get-away speed of 62 miles per hr. is given 


K S 0.06 and ~ 
37o 


= 0.00016 






below for 


varying 


percentages 


of the get-away speed. 






Angle of 
















attack, deg. K x 


X 10,000 K 


X 10,000 


K l/ K x 


W 











0.62 


4.3 


6.3 


6,500 








2 


0.65 


8.5 


12.2 


6,500 








4 


0.88 


12.3 


13.7 


6,500 








6 


1.20 


15.5 


12.6 


6,500 








8 


1.65 


18.7 


11.3 


6,500 








10 


2.06 


21.6 


10.5 


6,500 








12 


2.55 


24.4 


9.5 


6,500 








14 


3.30 


26.4 


7.8 


6,500 








16 


4.85 


27.3 


5.6 


6,500 




Per cent of 


Get-away 


Speed r 


A< P er cent 


A.lb. 


A/R 


R 


RV 


EIIP 


10 


6.2 


99.00 


6,430 










20 


12.4 


95.70 


6,220 


9.80 


635 


7,880 


21.0 


30 


18.6 


91.00 


5.910 


4.90 


1,205 


22,400 


59.8 


40 


24.8 


84.00 


5,460 


4.6.5 


1,172 


29,100 


77.7 


50 


31.0 


75.00 


4,870 


5.40 


903 


27,100 


72.3 


60 


37.2 


64.00 


4,150 


6.15 


675 


25,100 


67.0 


70 


43.4 


51.00 


3,310 


6.10 


543 


23,600 


63.0 


80 


49.6 


36.00 


2,340 


5.30 


442 


21,800 


58.2 


90 


55.8 


19.00 


1,235 


4.00 


309 


17,300 


46.2 


100 


62.0 


0.00 














.\KHOIM..\\K AM) SK.MM.ANK ENGINEERING 



261 



I).\T\ <>\ on i i KI M rrPBfl "i I II INC BOAT* 



Wright. fnll> |,..,(l,-<l. ll> 

fs.-flll 1.1.111. Ml 

M.ixiiiiiiin speed, miles JUT hr. 

Miiiiniiiiii speed, mill-- |KT hr 

Initinl i-linili. ft 

II span. ft. -in 

II length, ft. -in 

II height, ft. in 
Chord, ft. -in. 

' rra. s(|. ft 

Hull length, ft. -in. 

rryinj; a loail of .'l.'.Mi ML 

\in- .-, I., i, I ,,i 



ll> 1 


II l', 




S. 1 




10.900 


13JOOU 


. 




,%400 


4,740 


7,740 


M 


94 




-i 


44 


46 


47 


61 i 


i',400 to 3,000 ill 10 min. 


3,000 In 10 min. 


i lo min. 


< in '. min 


; i o i" 


94 13/16 


103 9 1/4 


IM 


38 4 14/16 


46 11. : 


49 3 11/16 


68 1 i/3i 


II 71/4 


K * 4/8 


18 9 1/4 




6 3 4/39 


1 49/64 


8 


I. 1 


tat 


I.U.I 


:..'.. 




34 3 


3 




II 7 



> \t a speed of 1,7 miles |KT hr. with n load of .M;JI- II.. 



The Discussion 

CUT. \\". I. CnvMiim-: As to tin- most serviceable 
si-;i|>l:iin- type at present. I ran conceive of tin service 
abilitv of the following general iiutlinr: (I) One middle 
Hoat entirely riu-loscil. without cockpits. machinery or 
carpo capacity: .' i a short miilillc fuselage located above 
the middle flont. with engine, pusher propeller, cargo space 
.iiicl forward L;IIII mount: ( .'i 1 two whip fusclapcs. forming 
supports tor the tail, a la Caproni, each with engine 
propeller and rear pun mounts : i H two smaller 
whip floats for lialancinp ]>nrposi-s. not at the whip tips, 
but located under the tractor propellers of the wing fuse 
the tail planes comparatively near the main 
ones and n--' d so that they may he utilized, in a fixed 
position, to afford inherent stability on lonp steady tliphts 
and yet be capable of mobility in response to any demands 
for quick manciivcrinp. While I do not suggest any 
finality as to model or type of either powcrplant or rig 
of the plains. I do not hesitate to predict, however. 
that future modification ami improvement will depend 
.pon further improvement of the powcrplant than 
on any other factor. (Ireat improvements in tlii. part 
of the aircraft an due. and each decisive step will result 
in a modification of airplane types for each specific pur- 
!>,.*, 

OIIMIII WiniiiiT: Commander Richardson's figures 
for the performance of propellers arc based on tables de- 
Tom experiments with models. The trouble with 
tables ,,f this kind comes from the fact that it is most 
iilficult to determine the exact value of each of the fac- 
lors which play a part in the pro|M-llcr's efficiency. The 
re- made with several variable factors, so that the 
measurements secured really show the result of the sum 
if these variables. The exact value of each one is not 
ued. I am of the opinion that much closer cal- 
ulatioiis .an IH- had from a theoretical consideration of 
M lions that must take place in a propeller. Cotn- 
n.-ind. r Richardson tinds that a propeller '.i. t ft. in 
r. driven by a Liberty engine, turning at Minn 
r.p.m. and developing :fSO b.h.p.. in traveling forward at 
niles per hr.. would have an efficiency of 
i'.' p- r cent, or a loss of only SI per cent. I believe it 
an ! show n that the loss from slip alone, without con 
<idcring any of the other losses, which also would be 

would IM* more than the amount he has found. 
When the thrust is known the slip can be determined 
asily. because slip is merely the acceleration imparted 



to a mass of air by the impact of the profiler I 
Slip, therefore, must lie equal to /'= V <<7*. <" which /' 
is the velocity; g. gravity or .S2.17 ft. per sec.: I,. head or 
pressure. Air at sea level may be considered as weighing 
I'.nrii- II,. p.r cu. ft. or I :t. !.': cu. ft. of air weighs I Ib. 
Ileiice a pressure of 1 Ib. per sq. ft. would accelerate air 
at sea level to a velocity equal to 



V *x!W.1 7x13.1 23 ft. per scr. 

But it is well known that the rate of acceleration is di- 
rectly proportional to the force and inversely proportional 
to the mass. Therefor, acceleration will In- proportional 
to the pressure divided by tin- volume of air. The pr.-s 
sure of 1 Ib. per sq. ft. will accelerate Hit eu. ft. of air 
to a velocity of 1 ft. per sec. or 1 cu. ft. of air to HU ft. 
per sec. The acceleration imparted to any other number 
..f cubic feet of air can be expressed by the formula 



Acceleration = 



844 x pressure In Ib. per *q. ft. 
Cu. ft. of air acted on 



The number of cubic feet of air acted on p. r square 
foot of disk area of a propeller is equal to the distance 
the propeller moves forward plus the acceleration or slip 
of the air acted on. Therefore 



Slip - 



844 x thrust In Ib. JKT sq. ft. of disk area 



Advance In ft. + slip in ft. 

If the propeller considered by Commander Richardson 
had an efficiency of <i:i per cent at HO miles per hr. it 
would have a thrust of 1220 Ib. Therefore the thrust 
would be 17.72 Ib. per sq. ft. of disk area. In the formula 
for slip just given, substituting 17.7-2 for the thrust in 
Ib. per sq. ft. of disk area, and 117.28 for the advance, 
,| th. slip equals Tti.'.Ki ft., a loss of S'.MSii per cent. 
It is therefore evident that it would IK- impossible to se- 
cure an efficiency of li'.i per cent with any pro|>cllcr of 
!>. > ft. diameter consuming :isn h.p. while advancing HO 
miles per hr. I have made a rough calculation of the 
performance such a pn pellcr should give, based upon the 
propeller being considered merely as airfoils traveling 
in a spiral course. A prop. Ih r H. I ft. in diameter work- 
ing under the conditions stated would have a thrust of 
approximately !>.SO Ib. ; the slip would amount to M.I per 
cent of the total amount of air the projK-ller traveled 
through, and the efficiency of the angle of advance would 
be 80 |MT cent. The total efficiency would therefore Iw 
0.65 x 0.80 or 52 per cent. 

Commander Richardson uses a method of calculating 



262 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



the rate of climb of an aeroplane which seems of doubt- 
ful value. He makes no allowance, so far as I can see, 
for the extra loss in efficiency of a propeller when climb- 
ing. The thrust in climbing must be approximately equal 
to the thrust when flying at the same speed on a hori- 
zontal course plus the total weight of the machine multi- 
plied by the sine of the angle of climb. It is apparent 
that if the machine were to climb in a vertical course the 
propeller thrust would necessarily have to be equal to the 
entire load of the machine. On an inclined course the 
propeller would have to bear a proportion of the entire 
load plus the thrust necessary to give the machine the 
desired speed. When climbing, the propeller efficiency is 
especially low in small-diameter propellers, because on ac- 
count of the extra load imposed, the slip becomes ex- 
cessive. 

COMMANDER RICHARDSON: A great amount of theo- 
retical work has been done on propellers, taking it from 
all points of view, but in my opinion none of these meth- 
ods of analysis are as satisfactory as the wind-tunnel 
methods, because even the theoretical investigations re- 
quire the use of coefficients which must be developed 
from experience or practice. And I believe that when a 
propeller shows 59 per cent efficiency in a wind-tunnel 
test, where the quantities can be actually measured, that 



this is the real efficiency of the propeller in question un- 
der the conditions of the test, and no amount of mathe- 
matical or theoretical investigation will convince me to 
the contrary. The airplane horsepower required curve 
shows the horsepower required to propel the plant at any 
angle of attack, and this is relative to the air and re- 
gardless of the path of the plane. The horsepower avail- 
able depends on the characteristics of the powerplant, in- 
cluding the engine and propeller and, as I clearly dem- 
onstrated, the propeller efficiency is a function of the 
speed of advance or the quantity f'/ND. The curve of 
horsepower required, therefore, shows at any particular 
speed of advance of the airplane the actual horsepower 
effectively delivered by the propeller, and the difference 
between the power required to propel the plane and the 
actual power available is available for lifting. The brake 
horsepower required of course is much greater, but in 
the computation of the horsepower available the effects 
of the reduced speed in the climb are taken care of. The 
propeller chosen for the example was selected for the 
purpose of illustration and not because it was the most 
efficient possible. Both Eiffel's and Durand's experiments 
have shown that efficiencies as high as 80 per cent are 
entirely possible. 



I HAPTKK V 



NAVY DEPARTMENT AEROPLANE SPECIFICATIONS 



The general specification- of requirements issued by the 
Navy Department for use in connection with contracts. 
and the submission to it of new and undemoiistratcd de- 
s of aeroplanes, ire interesting as indicating broadly 
tin- state of the art from the standpoint of this arm of 
the (ioxcrmncnt. The s|>ccitications are comprehensive, 
and give clear evidence of ability and knowledge having 
been applied in the preparation of them. 

Although the requirements which are summarized be- 
low in ] irue part, may IM- modified in the case of com 
pleted aeroplanes available for demonstration, sufficient 
information is essential in any ex t-nt to permit reasonable 
verification of claims of performance and as to strength. 

No new project will he encouraged unless it promises 
a marked adx nice oxer planes in service or already under 
trial, (in -it consideration will be given to possibilities 
for immediate manufacture, facility of upkeep and rapid 
dismounting of engines, and reduction of general dimen- 
sions. 

(icneral arrangement plans, one-twelfth or onc-twcnty- 

fourtli full size, showing plan, side and front elevations. 

to be transmitted. The following are to be indicated: 

Over-all dimensions, and principal dimensions of por- 
tion- -hipped partly assembled; 

Gap. chord and stagger. 

Positions and angles relative to the propeller nr:is for 
the main and auxiliary surfaces and floats; 

ion of center of gravity of aeroplane for full load 
and light load as defined under Rules Governing Conduct 
of Trials; 

Position of center of buoyancy and corresponding wa- 
ter line of the float sxstem when at rest on the water with 
full load: 

Portion of axis of landing wheels relative to center of 
gravity for full load; 

.ranee of the pro|x-llcr: For tractor tyjx-s to be 
shown with the propeller axis horizontal; for pusher 
ty|M-s to IM- shown with the aeroplane in position at rest 
on the surface; 

Angle of attack at rest on the surface under full load ; 

Areas of main and auxiliary surfaces; 

Dihedral angle; sweep back; wash-out or permanent 
warp, if any. 

The detail plans called for are: 

Details of spars, showing full sixe of the spar section 
in icli bay; 

- 'ion of aerofoil, showing with dimensions the posi- 
tions of the spars and details of wing ribs; 

Details of wing .struts and drift struts, showing full 



sise the central cross-section-, and details of taper, if 
any ; 

I >. tnls of typical strut terminal fitting and wing spar 
titling, with anchorage to wing spar and to stagger, lift 
and landing wires; 

Details of hinge connection between wing panels; 

Details of aileron, elevator and rudder hinges and 
horns, and general construction plans of thisc surfaces; 

Details of float construction, including lines and a state- 
ment of reserve buoyancy. 

The required assembly plans are those showing: 

The arrangement of all control leads and types of fit- 
tings used with them; 

The installation of compass, instruments, armament or 
other special gear. 

Arrangement of wing wiring, including lift and land- 
ing wires, drift and stagger wires, and tabulated strengths; 

Landing gear and shock absorbers, size of wheels, tires. 
axles and struts ; 

Propeller proposed, including section and angles at sta- 
tions o.l ;>. O..SO. o. r.. o.0 and 0.90 of radius; 

Mounting and general installation of the engines, with 
oil and gas tanks, starting, air intake, exhaust, and all 
piping arrangement; 

Cowling and ventilation arrangements for engine and 
cooling -y-tem. giving complete specifications of radia- 
tors employed. 

These further data are asked for: 

Detailed tabulation of estimated weights, showing 
weights included in light load and full load with the cal- 
culation of the locution of the center of gravity vertically 
and horizontally for each of these conditions with refer 
ence to the front edge of the lower plane with the pro- 
(M'llcr axis horizontal ; 

Diagram showing loads on the principal members of 
the wing and body truss, including a tabulation of the 
characteristics of the principal members, their loads and 
stresses under the several conditions specified under Fac- 
tors of Safety ; 

Calculated performance chart, showing the curve of 
effective horsepower required, the propeller efficiency, and 
the effective horsepower available, all based on velocity 
of advance in miles JMT hour; also a curve for the engine 
employed, showing brake horsepower plotted against rev- 
olutions per minute; 

A statement of the type and principal characteristics 
of the engine proposed, together with oil and fuel eon- 
sumption per brake horsepower hour; 



264 TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



A statement of the performance with full load at sea 
level including: Weight, full load; useful load; maximum 
speed ; load in pounds per square foot of plane area, in- 
cluding ailerons; load in pounds per horsepower; climb 
in 10 minutes; tank capacities for fuel and oil; endur- 
ance at full power at sea level. 

The aeroplane must have construction permitting fa- 
cility of observation, inherent stability, ease of control 
and comfortable installation for the crew. 

The general specifications are to be construed to include 
Bureau of Construction and Repair and Bureau of Steam 
Engineering detail specifications in effect at the respective 
date. All materials and processes are to be in accordance 
with any such detail specifications; otherwise, in accord- 
ance with trade custom as approved by the inspector. 

It is stipulated the contractor shall provide all material, 
parts, articles, facilities, plans and data to conduct all 
trials. Non-metallic materials, such as dope, glue, var- 
nish and ply-wood, are supplied by firms on the approved 
list of the Bureau of Construction and Repair. 

Inspectors may reject peremptorily any inferior work- 
manship or material. The contractor has the right of 
appeal to the Department, whose decision is final. 

The contractor is obligated to furnish under the con- 
tract, without additional cost, such samples of material 
and information as to the quality thereof and manner of 
using same as may be required, together with any assist- 
ance necessary in testing or handling materials for the 
purpose of inspection or test. The passing as satisfactory 
of any particular part or piece of material by the inspector 
will not be held to relieve the contractor from any respon- 
sibility regarding faulty workmanship or material which 
may be subsequently discovered. 

As soon as work on the contract is started the contrac- 
tor is on request to prepare for approval a full-size model 
of the cockpits, showing the general arrangement and 
disposition of seats, safety belts, controls, instruments 
and accessories located therein. The object of this is to 
test the feel of the cockpit for roominess, convenience of 
control, suitability of location of -all parts and amount 
of view afforded. 

Engines, armament, instruments and accessories will be 
supplied by the contractor or by the Department, and be 
installed by the contractor in an approved manner and 
location. 

The engines, armament, instruments or other fittings, to 
be supplied to the contractor by the Department will be 
free of cost, but the contractor will be required to fit them 
in the machines at his own risk and expense, and be solely 
responsible for carrying out successfully the requirements 
of the specification. 

Alterations and substitutions will be permitted only 
upon the approval of the inspector in charge but wher- 
ever such alterations may affect the contract plans and 
specifications, the aerodynamic qualities, structural integ- 
rity, or military characteristics, such approval must be 
obtained from the Department through the inspector in 
charge. 

All changes approved by the bureaus or requested by 
them will in general be of two classes: First, those of 
immediate military importance or necessary for safety, 
which will be incorporated in all units at once, and new 



parts shipped after units already delivered, so that the 
stations may incorporate the changes; and, second, 
changes which are desirable but not so urgent as to war- 
rant interference with production. 

In case of the first three machines of a new type, all 
material of every description placed on or attached to the 
aeroplane is to be weighed, together witli all material of 
every description which, after being weighed and placed 
on or attached to the aeroplane, is removed ; and such 
weight and description of the part weighed in all cases 
reported to the inspector. 

Where material is assembled before being weighed, the 
center of gravity of such assembly is to be ascertained. 
The center of gravity of each part or group of parts en- 
tering into or attached to the aeroplane must be reported 
in relation to the front edge of the lower plane with pro- 
peller axis horizontal. 

Parts which are partially or completely assembled be- 
fore installation are photographed and prints supplied. 
In addition, photographs of the complete assembly are 
to be submitted, giving the maximum amount of detail 
in not less than four positions. 

PLANS AND DATA 

One set of general arrangement plans shall accompany 
each aeroplane for use in erection, together with a set of 
instructions for erection; also construction specifications 
of the aeroplane; specifications and statement of sources 
of supply of all wood, veneers, metals, forgings, stamp- 
ings, wire, cable, glue, fabric, dope, paint, varnish, tub- 
ing, pulleys, tanks, etc. ; description of practice followed 
in seasoning wood and heat-treating metal, finishing fabric. 
securing fabric, making wire and cable terminals, rust- 
proofing of steel parts, waterproofing of wood parts : and 
statement of the parts that have been brazed, welded or 
soldered. 

Landing Gear 

The landing gear must be of an approved design and 
construction. Location of the wheels shall be such as to 
prevent any undue " spinning " when landing down wind 
under conditions specified. Particular attention will be 
given to simplicity of design, reduction of head resistance, 
and the least weight consistent with the service intended. 

Staunchness of construction is required while disposing 
material to greatest advantage, transmitting loads by 
suitable fittings and fastenings into the principal members 
and through them to the structure as a whole, in order to 
obtain strength without excessive weight. If at the same 
time resilience can be obtained it will be an advantage. 
and shock absorbers may be employed if their introduc- 
tion involves improvement in performance. Streamline 
form is desirable but must not be permitted to affect sea- 
worthiness. 

Water-tight subdivision is required as well as suitable 
access and drainage for each compartment. Hulls hav- 
ing double bottoms to the step, are to have suitable drain- 
ing arrangements incorporated in this false work. Drain- 
plugs and handhole plates are required on tail and wing-tip 
floats as well as on main floats. Flying boat hulls are. 
provided with a hand bilge-pump and means for pumping 
out any compartment when the craft is adrift at sea. 
Double skin boats shall have cotton sheeting and marine 



NAVY DKI'AHTMKXT AKKOIM.AN K SI'K( 1 1 1C A 1 K >N s 



glue U-tween tin- plvs. Hulkhcads should In- utilized AS 
.strength incinlirrs :uul he reason. ihlv w all r tight for at 
least twelve hours. 

'I'lir form "I tin liiittnin should be such as ID permit 
casv planini: Hilli longitudinal control. Tin Inrui slionlil 
:I|MI ! such is In rrilurr tlir shock of landing or of run 
ning .it high speed on lough water. Tin stahilitv when 
afloat ill .-i nnuli r id M -a with alii our compartment of nilV 
omplclcly or partially Hooded, slinnlij In- such that 
tin- seaplane will not roll or tip ti\rr. 1'rovision is re 
(|iiirrd against bursting dm- to tin- change in pressure 
involved in ascending to tin- maximum altitude contem- 
plated in tin- ili si^n. anil tin lirst lloat of a new type may 
iectcd to in internal pressure corrcspondiii'.; to this 
altitude. Suitable skills, kn-N, edge strips, footliolils. 
walking sirips, etc.. an- required to prr\cnt undue chafe 
ami we.-ir in service. Towiny cleats .mil nose rings shall 
In "I :ipprii\cil design ami location. 

All internal nirtal lillin^s ami all fastenings shall lie 
copper or brass, ami all \ti rnal metal |iarts shall 1'e ade 
quatclv proteelnl against the action of salt water. 

llolis lor fastenings are to he carefully bored and care 
(akin I" avoid splitting the wood. Units and clinched 
lioal nails are to I r used in preference to screws wher. \er 
possilile. 1 )i id nails are not to he used. dim- should 
not he n lied upon as a jointing material in any lioat or 
float work. Anv splice, in strength nu inU-rs must IM- 
.secured hy copper rivets and if possible In whipping ill 
addition. The type of splice shall in any case he sub- 
mitted for approval. Any propeller which has not a float 
directly heneath it is to he so situated that clearance IM-- 
the propeller tips and the water is not less than 
two ft. when the seaplane is afloat at rest, or is afloat 
1 with the tail lifted to the Hying attitude Pro- 
peller clearance immediately over floats should be at least 
two in. 

Body 

The form and disposition of body members and fittings 
are such as to provide positive alignment and minimum 
distortion under the loads to IM- met in service. For sea- 
plain s. the crew must IK- able to get out quickly in cas, 
idcnt. Suitable footholds are to be provided to 
enable (lie crew to pass to the main floats and to the 
engines to make minor adjustments while the machine is 
afloat. 

Longitudinals may In- spliced only in approved manner. 
Longitudinal fittings shall IM- properly anchored to take 
shear, but through-bolts should be used with caution. All 
wins used for trussing arc to IM- solid except where read- 
ily acctssiblc. or where the use of other types is ap 
i. A suitable windshield is to In- fitted to each 
cockpit. For each seat an apprised safety !M-|| will be 
supplied. Kcmoxahlc seat cushions are to IK- so attached 
that they cannot shift when in flight. 

Engine Installation 

1'or seaplanes the engines shall be capable of being 
1 by the crew when the machine is afloat in a sea- 
way. The engines shall lx- accessible and easily removed 
and replaced as a unit with a minimum disturbance of 
fittings. 

Kngincs arc to be effectively cowled with sheet metal, 



with parts easdx remo\able for access ( owls for rotary 
engines shall protect crew, planes mil Uxly from oil and 
smoke Tin exhaust is not to interfere with tin crew, nor 
is (here to lie any 1 1. -1111:1 r of fire due to it. 
mufflers are to be provided unless s|M-cfically < xei -pled. 
Approved provision is to I., in idi tor the .nlrin. 
exit of air for the purpose of cooling |h, , ML :mc base 
and cylinder heads. In tractor aeroplanes a flame tight 
metal bulkhead immediately hi Inn. I the engine is provided. 
Means are installed in the pilot's cockpit for extinguish- 
ing lire forward of tile fire bulkhead. The body beneath 
lyine has a imial cover sloping In the rear with an 
opening at the r. .r . il^. extending the entire width. The 
Ivottom of the body hi hind this point is to be ..,\, red ith 
metal for at least three feet. Suitable drip-pans and 
drainpipes leading clear of the body are to lie provided to 
get rid of gasoline overflowing from the carbureters or 
elsewhere. Carl ureter-float covers shall be so si cured as 
to prevcir ,.l ^'isoline. Careful consideration 

should he given to conditions surrounding air supply to 
the earbureti r In insure that spray and rain are not drawn 
in anil that freezing dix-s not o.-ciir in the carbureter or 
induction pipes at high altitudes. 

A head of at least .'. in. shall remain above the outlet 
li cylinder when the reserve water allowed has been 
boiled away or otherwise lost, and with the machine in- 
clined upward -' ' (leg. to horizontal, or K) deg. list to 
either side. Radiators shall be tested filled with air at 
S Ihs. per sij in. pressure when totally immersed in water. 

Foundations 

All foundations for engines, radiators, seats, control 
gear, guns. I., .nil. storage, releasing gear. etc.. are to IM- 
thoroughly supported from panel points. 

Fuel Tanks, Piping, Etc. 

Fuel tank location is nearly central. Gravity feed to 
irburetor. under normal conditions of flight, or a 
service tank having at least a half-hour capacity, is pro- 
vided. I .11 h tank has independent leads either to the 
service tank or carbureter. If gravity feed cannot IM- ob- 
tained, proper and approved means in addition to a hand- 
pump, are provided for supplying the service tank. F.rfi- 
cicnt strainers arc required in each fuel-tank lead. All 
solid piping shall IM- annealed after bending. All joints 
shall IM- brazed. 

Fuel tanks shall be tested with an air pressure to give 
three pounds per square inch at the carbureter without 
showing leaks or unreasonable deformation. Swash-plate 
bulkheads should IM- tilted and the heads so formed n to 
prevent vibration. If gravity feed is used, the tank shall 
IM- fitted with a suitable vent, which will close mil pre- 
vent leakage of gasoline through the vent in case the air- 
plane turns upside down. Tanks shall IM- non corrosive 
and made of annealed material where possible. Filling 
caps are to IM- secured with chain lanyards. 

All gasoline, oil and air-pi|M- joints are to IM- electro- 
conductive, .-md where the joint has to lie made with an 
insulator, such as rubber tubing, it must IM- short circuited 
by an approved method. The gasoline and oil supply are 
to be so arranged that the delivery of gasoline and oil will 
continue under the normal air pressure (if no fitted) until 



266 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



the tanks are empty, in any reasonable position of the 
machine. The ignition and auxiliary circuits must be 
thoroughly protected from short-circuits by spray. A 
positive means of quickly cutting off the gas at the serv- 
ice tank shall be readily accessible from either seat. The 
fuel leads, the control leads, and the carbureter adjusting- 
rod shall be provided with suitable, safe and ready coup- 
lings where those connections have to be frequently broken. 
The oil thermometer bulb shall be installed in the oil- 
sump or other approved location where it shall be covered 
with oil at all times. The circulating-water thermometer 
bulb shall be installed in the outlet pipe of the engine 
near the radiator, or in other approved location. 



Controls 

Plans showing the general control system shall be ap- 
proved before installation. All control gear and control 
cable shall be readily accessible for inspection and lubri- 
cation. The control surfaces and actuating mechanism 
shall be so arranged that under no circumstances shall 
they jam or foul, and the whole system shall have an 
approved margin of strength and rigidity. 

All control gear shall be so placed that it will be pro- 
tected from sand and dirt. Control wire shall be kept 
away from floors. 

All control operating horns shall be relieved of bending 
stress by at least one wire unless otherwise approved, 
and control columns, posts, bars and pedals shall be pro- 
portioned to prevent bending in service. 

Welding of control horns is prohibited except for longi- 
tudinal seams. 

All control leads shall be of stranded cable of an ap- 
proved flexible type and make, and shall be thoroughly 
stretched before fitting. Where the control lead passes 
around a pulley or drum, the wire shall be guarded against 
coming off. Such guard will not be approved if the cable 
can be forced off its pulley or drum when quite slack, by 
pushing the two ends of the cable inwards with the hands. 
All control pulleys shall have ball bearings. The radius 
of curvature of pulleys or fair leads for control wires 
shall be not less than fifteen diameters of the wire for a 
90 deg. bend. The turnbuckles in control wires shall be 
in approved positions as far as possible from the compass, 
and accessible for adjustment. 

The handwheel, if employed, shall be made exclusively 
of non-magnetic material with the inner edge of the rim 
corrugated. The rim shall be fastened in a secure man- 
ner and the use of wood screws for this purpose will not 
be allowed. 

Each elevator half is to be provided with one pair of 
operating horns (or their equivalent), each with independ- 
ent leads. 

The steering is to be by means of foot bar or pedals, 
adjustable fore and aft for at least six inches. Arrange- 
ments are to be made to prevent the pilot's foot slipping 
off the foot bar or pedal. If a foot bar is used, guides 
are to be fitted to prevent vertical play; also stops suffi- 
ciently high and strong to prevent the bar bending or 
overriding them. 

The controls need not be non-magnetic for the trials, 
but if the compass is affected, replacement with non-mag- 
netic gear is to be made. The fixed control fittings should 



preferably be non-magnetic, but permission may be given 
to use magnetic fittings if it is considered that there will 
be an advantage in weight, strength or convenience 
manufacture. 

If, on the engines employed, the throttle and magr 
advance levers are interconnected and brought to a single 
lever, this lever shall be operated by a separate hand- 
lever for each engine. When the throttle and magneto 
are not interconnected, a separate hand-lever shall be 
provided for each engine, these systems being so arranged 
that the pilot can control with one hand the engines in- 
dividually or together. The hand-levers to the throttle 
and ignition and to the engine switches, in case of ma- 
chines carrying two or more pilots, shall be arranged by 
duplication and interconnection of levers, so that either 
pilot can operate them when in flight. The forward posi- 
tion is to be the position for full power. Each throttl 
or magneto advance lever is to be fitted with an approved 
system of positive location. A spring, capable of open- 
ing the throttle in the event of the control gear breaking, 
is to be fitted at the engine end of the throttle-control 
system. The engine switches are to be of an approved 
type and so placed for each engine that all can be moved 
simultaneously with one hand, the direction of motion 
for shorting to be approved. Ground wires for switches 
are to be led direct to the engine and not to the engine 
mounting. 

Wings 

Spruce or Port Orford cedar for wing spars shall be 
selected from the clearest, finest stock available, shall 
have a density in excess of 0.36 and 0.42, respectively, 
based on oven-dry weight and volume, and, if possible, 
more than eight rings per inch. 

The spar shall be suitably increased in dimensions where 
it is pierced by bolts. Particular attention is to be given 
to this point when the spar is pierced by bolts not approx- 
imately on the neutral axis. The fitting and its method 
of attachment to the spar shall be so designed that the 
failure of any part of it shall not cause the struts to be 
displaced or both the flying and stagger wires to be re- 
leased. 

Either brass or galvanized-iron brads shall be used ' 
fasten cap strips to ribs; but brass screls shall be used 
to fasten cap strips to spars. 

In order to prevent relatively weak portions of the 
machine from damage in handling, hand-grips shall be 
fitted in suitable positions near the extremities of the 
lower planes. 

Control Surfaces 

All ailerons shall be double-acting. For large machines 
in which control by means of unbalanced surfaces will be 
obtained with difficulty, balanced surfaces of approved 
form shall be provided. 

The horizontal fixed tail surface shall be so designed as 
to permit of adjustment in angle. Arrangements may in 
some cases be made for this adjustment while in flight. 

Elevators shall be on same axis tube or locked together 
in such a manner that the control is not rendered useless if 
one set of control wires breaks. 



Wing Struts 
Wooden wing struts, if hollow, shall be taped, dopec 



NAVY DKl'AirrMKNT A Kl >1M..\ \ I SPE4 II li \l|,\s 

and xarmshed. Any *** subtly warped will be operated bx -,, - ,,,, mrtlMcnt mnv 

rejected. \ ooden ,,ru, shall ,d, ., .,, ,,,.,,, , , J 

spruce. I'ort Ortord cedar or white ,,- of finest grade. .ilenm load*. 






close grained ind Hell -eason, ,i. I or struts the inspector 
will select -prucc or white |>itic ha\ing :i <j< n-jt\ in 
of (>.. 'Hi or I'ort Orford c, dar li:i\iu^ a dcn-itv in excess of 
and. if possible, more than eight rinijs per inch. 

Propellers 

Tli. propeller hub fncepl.it,-, shall be intcrconn 
imlcpi -ndent.y of tin- propeller bolts, so that each plate is 
used to drix, the propeller. Wood propellers shall be 
fitted with sheathing wlii<-h sh.-ill extend a distance from 



The total lift load ..n each wing in ih. product of thr 
f that wing by it, i,.,,t load ,n,l a ,-,. d to U- 
applied uiiifonnly .ilon K the -pars .-,, l( | di-trihulcd b. 
them , imrr-c pro|M.rlion to their chord di-lancc, from 

'MM. ,1 center of pressure. At high -p,,-,| i|,, 
t. r of pressure -lull IH- assumed at (..'. of the chord di, 
In... from the leading , ,, t when r ,.|, ,|,| ( . , 

tunnel data on the center of pressure trax.l and , 
plane life .-..crticicnts for the aerofoil employed are axail 
able, in which ease the center of pressure for high 



Non-corrosive 



the tip of the 1.1.1,1, toward the center approximately on, mix l- calculated from the wing loading it high 

rth the diameter on the leading edge . m d ,-ight inehes by obtaining the riving angle from the monoplane lift 
on the trailing edi;., is a iiiininiuiii ; detailed requirement- characteristic. At low -| H -ed the center of pressure shall 
may be found in Bureau of Steam l-'nginci-ring. Instriic- be taken at (l.-.'H of the chord distance from the I. 

edge, mil, ss an unusual aerofoil i- employed, in which 
he center of pressure travel may be modified if data 
from wind tunnel tests are available. 

I!. -ides the lift load defined alx.xe. the wings carry a 
drift load which may U- assumed equal to one-quarter the 
lift load and applied at the center of pressure. Tin- drift 
is assumed to include the drift of wings, struts, wir- 
ap|H-ndages. \Vherc data from wind tunnel test* arc 
quoted, the fraetion of lift applied horizontally as drift 
may be altered. Thi.s drift load may then IN dni.l.d 
Let ween the spars and distributed uniformly along them. 
Kesolve the running lift and drift loads for each spar 
into a single running load in the plane of the principal 
axis of the spar and. making use of the Theorem of Three 
Moments, compute the bending moments in the spar and 
the reactions at the joints or points of support 

Assume, as a first approximation, pin joints with all 
loads concentrated on joints and compute direct sir. 
each member after having nsoUed (he loads into the 
planes of each group of member- i. c.. plane of front 
struts, plane of chord of top wing, ete. For apart, com- 
bine the direct -tresses due to lift and to drift with the 
stress due to bending. 

The horizontal ihrar in the wing spar- -hould br com- 
puted for section- near the strut ends where the par h* 
its usual section. 

Directly over the strut- the wing spars shall not he 
hollowed out. and if pierced by holt holes allowance -hall 
be made in all computations for the sectional area of the 
holes. Wood spars of I -section shall have the web at 
least equal in thickness to the flanges and eut with gener- 
ous fillets. 

All splices iii solid wing spars shall be loeated at (mints 
of eontratlexiire or minimum bending moment. When the 
exaet location of these points is not known, they may be 
assumed to oeeur at from one-fourth to one-third the dis- 
tance between consccutixe interplane struts 

Splicing of iml.iiiun.it, d spars or of lamination* of lam- 
inated spars will be permit ted provided the type of spin, 
is appro* cd by the Department. 

In splicing solid wood spars of I-section the spliced fee- 
lion shall not le routed out. 

Fittings for pin-joints at butts of wing spars are to be 
designed so that securing bolts cannot crush or shear 
through wood under loads specified below. 



tion- for Tipping Seaplane Propellers. 
riiet- or screws shall IK- used. 

FACTORS OF SAFETY 

factors of safety specified apply in general to all 
aeroplanes. In all case- the burden of proof rests upon 
th, contractor to demonstrate by submission of his calcu- 
lations in detail that the aeroplane is structurally safe. 
Any part or parts whose strength is in doubt shall be 
tested by sand loading or other approved method. Thi.s 
specification refer- in particular only to the most impor- 
tant structural members. I'or foundations, terminals, tit- 
ting-, bra,-,- and minor structural parts, for which calcu- 
lation- an indeterminate 01 loading unknown, good en- 
gine, ring practice shall be followed. 

Th, wing truss con-i-t- of the wing spars, interior brae- 
rut- and exterior bracing together with all wire or 
cable anchorage-, but does not include non-strength parts. 
such is leading and trailing edge strips, ordinary ribs, 
tap,, doth, battens, corner blocks and fairing pieces. It 
nned that the wing truss carries in normal flight 
the full weight of the aeroplane and, in addition, the drift 
of the wings, struts, external wires and any appendages, 
such as skid fins, wing floats, etc. 

In biplanes the distribution of loading on the wings 
shall Ix- computed by the formula: 

11 

- + AX, (i) 

9 

in which W = total lift load, A* = area of upper wing, 
= area of lower wing, and x = unit load on the lower 

which is obtained by solving the above equation. 
In triplanes the distribution of loading shall be com- 
puted by the formula: 

5 3 

W = A-x -f A-x + Ax, ( 2 ) 

* 4 

in which A" = area of middle wing, and other notation is 
me as in ( I ) . 

-tresses imposed in the wing truss are figured from 
lift which equals the total lift less the weight of 

md the interplane bracing. 

Aileron- are considered as wing area, but in special 
when ailerons are of unusual design or si*e. or 



268 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Struts shall be computed as if made with pinned ends 
whether or not the ends are actually pinned. 

For it-ires and cables allowance should be made for the 
efficiency of the terminal. Similarly, the strength of the 
fitting to which the wire or cable terminal is secured must 
be considered in the wing truss design. Wires and cables 
should be so led as to introduce no eccentric loading on 
structural members and anchored in fittings designed to 
develop their full strength. 

The stagger wires are to be assumed to carry the drift 
of the top plane. Where the top plane passes over the 
body, the entire drift of the top plane is assumed to be 
carried into the body by the stagger wires and struts at 
that place as if acting alone. 

Cross transverse diagonal wires over the body holding 
the top plane from racking as the aeroplane rolls should 
be computed to hold the rolling movement obtained by as- 
suming an up load of 20 Ibs. per sq. ft. on one set of 
ailerons and an equal down load on the opposite set. 

Wood 

Air seasoning is preferred, but forced drying will be 
permitted if approved methods are used. Laminated wood 
shall not be used unless approved by the Department. 
Spiral grain will be allowed only as permitted in specifi- 
cations issued by the Department for each type of ma- 
chine in production, and in case of doubt test sticks shall 
be split. No spruce or white pine below 0.36 density, 
Port Orford cedar below 0.42 density, or ash below 0.56 
density in oven-dry condition shall be used in important 
strength members. Wood splicing shall be only as ap- 
proved. The splices shall be of efficient form and the 
grain shall not be turned. Bolts or rivets shall be used 
if required, and the joints shall be finally taped or served 
and glued as prescribed. 

All dope, enamel, paint, varnish, shellac, waterproof, 
hide or marine glue shall conform to Department specifi- 
cations. 

Metals 

Where the material is of a class susceptible of improve- 
ment in quality by heat treatment, such treatment shall be 
given as a final step in manufacture, except in the case of 
small parts. In the latter case the heat treatment shall, if 
practicable, be given before fabrication or else the parts 
shall be made from heat-treated stock. 

Steel shall not be left in finished parts in a hot-rolled, 
hot-forged, or cold-forged condition. Normalized steel 
must be renormalized after forging (hot or cold), welding, 
or otherwise heating. 

Hard-drawn steel must not be heated. 

Laminated fittings of metal which are brazed or welded 
shall, in addition, be thoroughly riveted. Welding and 
brazing shall be restricted to parts not otherwise possible 
of fabrication, and only in approved locations. 

Acids will be used in soldering only where expressly 
permitted. If used, after soldering, all acid shall be neu- 
tralized and washed out in an approved manner. 

Wire 

Solid wire shall be carefully formed to perfect eyes 
without any rebending, and the eyes shall be properly 
formed to prevent crawling. Eyes should be examined 



for signs of lamination and cleavage. Cable shall be 
tacked with solder before cutting or cut with acetylene , 
flame to prevent uneven stress due to unlaying. At the 
time of tacking the wire shall lead straight. 

Wire with hemp centers shall have the center locally] 
removed before making up the terminals so that the cen-l 
ter strand will carry no load. The ends of all cables, 
whether flexible or otherwise, shall be fitted with thimbles 
or other approved device to minimize slackening in serv- 
ice. Where cone cups are used for terminals the double i 
mushroom may be required unless the workmanship is 
such as to show by test perfect terminals in every case. 
Taper plugs shall not be used. All wire terminals except 
those of the cone-cup type shall be soldered. Cone cups 
will be puddled with zinc and care taken to prevent draw- 
ing the temper of the wire. 

Wherever wires are inaccessible for adjustment, as is! 
the case inside the wings and auxiliary surfaces or in 
parts of the body or floats, solid wire shall be used un- 
less otherwise approved. 

Cable stays shall be made up complete witli terminals 
and proof stretched before installation with a load equal 
to one-quarter of the ultimate tensile stress. 

Fabric 

Wing, body and auxiliary surfaces shall be covered with- 
linen or cotton conforming to Aeronautical Specifications, 
C & R Nos. 12 and 13, respectively. On the wings, the 
fabric shall be applied either diagonally or with stains 
running normal to entering edge. On the wings, the 
tape and lacing method shall be used, with loops spaced 
not more than four inches apart. The thread shall be 
knotted at each loop or made fast with a double half-hitch. 
and then cemented with dope. The tape used in wing 
construction shall be of the same quality of fabric as used 
for the wings. Tape used on laminated struts or built-up 
parts shall be applied with glue and then doped. Thread 
used for stitching seams shall be of an approved linen or 
silk and shall be waxed. 

Pontoon Fabrics 

In built-up laminated floats, bottom planking and bulk- 
heads shall include cotton sheeting applied with an ap- 
proved grade of marine glue between laminations. 

Requirements of Finishing Materials 
Acetate and nitrate dopes used on all work shall be ifl 
accordance with Aeronautical Specifications, C & I 
1 and 2, respectively. Spar varnish and naval gray 
enamel used on all work shall be in accordance with Aero- 
nautical Specifications, C & R Nos. 3 and 4A, respectively. 

Doping 

The doping of all naval planes, with the exception oj 
H-16 and F-5, shall conform to the Navy Standard Dop- 
ing System A. 

Navy Standard Doping System A 

Wings, control surfaces and fuselage fabric On all 
fabric two coats of cellulose acetate shall be applied 
This treatment shall be followed by the application of 
sufficient number of coats of cellulose nitrate dope no 



NAVY DKl'AHTMKNT AKKOI'I.ANK SIM-.C 1 1 It ATM )\ > 






le-s than two or more than four coats to obtain satis 
factory tautncss and tinisli. After the last coat 1ms dried 
for nut less than twelve hours. na\:tl gray rnamel .shall 
he applied: two .-oat- on \crtical surface, two coat- , IM top 
sides, and on.- coat on the under side of horizontal sur- 
faces. 

() I' l"> '"'I I planes, acetate dope shall conform to 
Navy Doping System B. 

Navy Doping System B 

Wings, control surface- and fuselage fabric On all 
fabric the successive eoat>. of cellulose acetate dope shall 
he applied. After the last coat has been dried for not 
less than twelve hours, naval gray enamel -hall lie ap- 
plied; two coats on vertical surface, two coats on top 
.sides, ami one coat on the under side of horizontal sur- 
faces. 

Finish for Metal Parts 

Plating '/.'me coating is preferred and should be used 
wherever practicable. When galvanizing is employed, the 
zinc coating should conform to Aeronautical Specification-. 
I \ H No. ;;<>. Special alloys and heat-treated steels may 
l>e affected if galvanized by the hot-dip or other proc- 
esses employing high ti-mperatures 375 to -150 deg. C. 
On such parts, as well as on accurately dimensioned small 
parts, the electro-galvanizing process (zinc plating) 
should In given preference. 

I 'leaning Sand blasting is preferred for cleaning 
metal previous to plating. Pickling of metal surfaces with 
acid should be avoided wherever possible, since pickling 
increases the brittleness of metal and has a very unfa- 
voral-le effect on thin stock. Pickling should especially 
be avoided on metals that may IK- subjected to continual 
vibration. Wherever pickling is used, the metal should 
I" thoroughly cleaned with water so as to remove the 
pickling acid previous to plating or finishing. Threaded 
and bra/ed parts are often cleaned satisfactorily in tum- 
blini; barrels with oil and emery. 

Painting After plating or coating with zinc, copper 
or nickel, metal fittings .shall IK- finishcl with enamel. 
Specifications (' & R No. lA gray or No. :> black. After 
assembly all metal parts that show bare places shall be 
touched up with enamel. Interior plated or zinc-covered 
fittings such as tubes or aileron horns and all such parts 
having cavities shall lie dipped in enamel and then allowed 
to drain and dry. This process is included to insure in- 
terior protection against corrosion. Steel tubes having 
sockets or caps on the end may be drilled with two hoi 
Thinned enamel may be poured in one hole and allowed 
to drain. After enamel is dry the holes should In- plugged. 

Wires and Cables 

All fixed external wires or cables shall be carefully 
cleaned and coated with spar varnish containing 5 per 

of Chinese blue. 

All fixed internal hull wires or cables and all internal 
wing wires or cables shall be painted with naval gray 
enamel. 

All control wires or cables shall be heavily coated with 
an approved grease. 



RULES GOVERNING CONDUCT OF TRIALS 

I 1<H,,1 Comprises the aeroplane complete in or 
ler for flight, includim; water in radiators, water and oil 

tl " r " "t-rs. tachometer, dashboard instruments, stnrt- 

ers, all tanks and gages and armor, but without those 
items included m t scful load." 

{'nil load Comprise.. () aeroplane complete us speei 
fied under " Light load " and in addition the I seful 
load." 

{'*rfnl load Comprises fuel and oil. crew, armament, 
equipment and accessories as detailed in the com, 

At the beginning of each trial of any performance, the 
aeroplane shall be brought to the prescribed " I nil load " 
condition. 

The first successful trial under the conditions p r . 
scribed shall be final, and no further attempts shall I . 
made. 

Throughout the trials the powerplant (including pro- 
peller) and the aeroplane shall be identical in even r. 
spect with that which it is proposed to deliver for KH 

The gasoline used shall be of a commercial grade read- 
ily procurable. 

Demonstration trials include the following, in which 
the aeroplane .shall meet the |x-rformancc requirements of 
the contract: 

(a) High speed, (t) Climbing, (r) Maneuvering on 
the surface and (d ) Maneuvering in the air. 

Immediately after each trial an inspection of the aero- 
plane and powerplant shall be made to determine that all 
parts arc in good condition and functioning proper! v. 

Not more than four official attempts will be allowed in 
which to make either the high speed or climb prescribed. 

The manner of conducting the high speed and climb- 
ing trials shall be as agreed upon. 

Maneuvering on the Surface 

Landing The aeroplane shall ! capable of being 
landed down wind with dead motor under prescribed con- 
ditions. Such landing shall be made with no tendency 
of the aeroplane to spin dangerously or to turn over on 
its nose. 

If required, the aeroplane shall be driven along the 
ground in a straight line in any direction <vith res|>ect 
to a wind of a velocity between 15 and 20 m.p.h. 

Maneuvering on Water 

Seaworthiness will be demonstrated by maneuvering 
the surface at anchor, adrift and under way. 

The purpose of such trials is to determine staunchness. 
stability, planing power and longitudinal and directional 
control under varied conditions of the wind ami sea. 
representative of conditions to be met by the ty|x- under 
consideration. 

In a calm, with full load, the seaplane shall steer read- 
ily. At all speeds up to " get away " the seaplane shall 
respond readily to the controls. It shall " plane " at 
moderate speed, accelerate rapidly, and get away within 
the distance specified. It shall show no uncontrollable 
" porpoising " or tendency to nose over at any speed. 
In.!, r this condition the pro|x-llcr should be free from 
spray and broken water. 

In a moderately rough sea the seaplane shall steer 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



270 

readily in all directions and at all speeds. It shall 
"plane" at moderate speed and without undue por- 
poising " or tendency to nose over under any condit 
with the wind forward of the beam. 

With the wind abaft the beam it should be capable ( 
running slowly or- at moderate speed without nosing or 
without undue spray or broken water entering the pro- 
peller disk. Down wind at wind speed there should 
sufficient reserve of stability to prevent nosing over 

Headed into the wind there should be no marked 1 
ency to yaw. 



In a rough sea the seaplane shall steer readily in all 
directions at moderate speed, and shall steer readily at 
anv speed with no tendency to yaw with the wind any- 
where forward of either beam. It should be able to get 
off and to land headed approximately into the wind w.tl 
out undue punishment to the seaplane or propellers. 

Adrift or riding to a sea anchor or to a ground anch 
the seaplane should not take any dangerous attitude in a 
calm, moderately rough sea, or in a rough sea. 



v ii API I.H VI 



METHOD OF SELECTION OF AN AEROPLANE WING AS TO AREA AND SECTION 



Bv .1. A it,,, ,,,. \| \ 



This ph-isc of design, although ,,f ,.,..,, imp,,,-!;,,,,.,. ,f 
the hitthest etfici, ncy is to ! attained, li.-is loin; |,, ,. 

'tl. 'I'll,- first reason for tins was (lie lack . 
pcrimental data on which i-,uii|i:ir:iti\i- calculations could 
be IMS,,!. ..,,! now that this datn is plentiful ami trust 
worthv. there is IIM ,|iiick -Hi, I easy way t.. I, -ad MM,- to t In- 
correct <-<unl>iriat i,.n !' section and area to he us,-,l. 

This dith'cultx aris.-s fnuii tin- tact that Imtli section 
and area ire funrlioiis of , ai-li other and also of tlu- 
weight, power, head resistance and intended purpose of the 
guchine. 

Aii\wa\. an aeroplane is pretty sure to fly satisfactorily 
rovidini: t |,.. lt die relation between tile aliove factors IH- 
hoseii with " ii..,.<l taste " or with nn eye on the nci^h- 
ior s machine. |,,,t there is ,-ver the doubt that the machine 

not at its liest - perhaps a ditT.-rent curve would be 
Me perhaps a little less surface would 1),- hettcr. 

One of the co on methods now used in making this 

11 consists in picking out the curve of highest lift 



to drift ratio available, and finding tin- area by mean* 
of the familiar formula: 



. 
\\hrrr: 



II = Ihr r i K ht ,,f thr mnrhlnr. fully loaded. 
K f = thr hlnhrst lift ,-.;, i,.,,t 

thr low |ifrd h>|>l for In in.p h. 
Ii thr rc sought 



It is generally assumed that the se<tion ehosen is the 
Ins the highest lift to drift ratio; l.ut no 
fair lest of the combination is had until the characteristic 
curves for the aeroplane are drawn. Moreover, to draw 
such curves for several combinations ,,f section and arra 
would require a great deal of work ami then the com- 
parison would lx- rather difficult. 

Vow I propose to demonstrate a method which I have 
found simple and satisfactory. 

In general, the problem presents itself as follows: 
Specifications require a certain climb, speed range, and 



' 



##>//>, 







tj 










J.H iwrwi' i 




I ! 



t I 



nil i-lvirt- 



271 



of 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



272 

useful load to be carried and we are given a power plant. 
There are seven variables to be considered, namely: 

K f , /v A, r, S, V, W. 
These are related by simple expressions: 
T = A 1' 



1 1 to allow for the greater efficiency of large planes 
moving at high speed. We can also multiply the area by 
1 08 to allow for the greater efficiency of the aspect ratios 
commonly used. Finally A, being affected by interfer- 
ence, can be multiplied by .1), the equations thus corrected 
become : \y 



Where K x c c inriirinary square plate whose air 

figteMe WOttld be equal to that of all the struc- 
tural parts of the machine, or to the pa. 
sistance. 
K = The coefficient for A 

sq. ft. X m.p.h.- 

nm-^ft ~" 

His. 

P = The power available in Ib. miles per nr. 

V, S, W, A" B as above 
From which we get by transposition and cancelation : 



It now becomes necessary to apply to these equations 
the factors that will make them yield results in terms of 
the desired units and those that will compensate for the 
following: Aspect ratio, reduction of size and wind 
velocity, interference or biplane effect. 

All possible care must be exercised in selecting these 
coefficients; they will be different for different types of 
machines the' following are not chosen with any type 
in view. Some valuable indications of these coefficients 
may be found in Loening's " Military Aeroplanes " and 
in Eiffel's books. 

Mr. Eiffel recommends that the area be multiplied by 



1.08 x 1.1 X 9 X 
KA 



K_=- 




- 1.1 xi.osxsr-i 1.1 x i.os x LIB -si- 
It would be more accurate to apply these corrections toj 
the characteristic curves of the wing sections tested; how 
ever the errors of this method are slight, and since 
same error is introduced in all cases, the value of thisj 
method is not impaired for purposes of comparison. 

Consider the graph of these equations, K, being plotted 
against K a for various values of V and for assumed co. 
stant values of -S, W, P and A. 

Note that these equations give the value of A, neceitart 
to flv and the values of X, available at various velocit 
Note also that the effect of the second term of 
equation is merely to subtract a constant amount from tl 
K. which would be available were there no head resistance 
This amount depends only on A and S and its value is real 
on the X, scale of the diagram. The effect of this term 
is then to displace the origin of the plot to the right alon| 
the A* axis. In order that this origin be easily locat 
for any possible value of A, which will naturally vai 
according to the dimensions of the machine, and for t 
values of S under consideration, a set of lines is drawl 
as shown on lower left-hand corner of wing select* 



CH/jftT rOR THE PETRr-IINRriON^ or . Jj^j;("' : " SS '"' rl CHKRT FOR 

I ' ' 

Mj-- 









ro\, 7V> eo" 



90 v too 
a.*. * 



AVinr selection diagram calculation charts used 



to facilitate computation of coefficients and calibration scale used to gra| 
diagram 



MFTH01) OF SFFFCTION OF AN A FI{()1M..\ \ F \\l\c. 



278 



agram. from which th<- valm origin thus 

1 . 1 ' x 

H-atcd fur any given Conditions. I'sing this in w origin 

, values remain as tiny were. but tin- new A v ili;. - in 

HIT that rrmniii to drive tin- wings alone through tin nr 

\" consider tin- |i|:ir curvis nl certain tested wing 

ctions; these curves tirst il. -vised b\ Mr. l.illil s, em to 

c by far tin- most ingi -nioiis method of represent in}; the 

ri^tics of a win.; MI linn, anil I wonilrr why their 

has not lieen more widely adopted in this eonntry. 

olar curvi -s can lie den\ed. however. from anv other 

i-ristie eiir\es available. nr translated to Ih. i|. 
if units and si/.e from tun inn polar curves. 

that these eurves give the A', rfijuirrtl by tin- 
i-tion to nio\e through the air nt various angles and tin 
av.iilal le with tin- section if it is made to travel at 
rioiis incidences. 
Then recalling the matter on page I- 

lie A rripiireil A 
lil.iMi -- A" v rr|iiirrl = A^ excess 
A . - - X AV- = Kxccsx power 

I I I MCM liftinp capacity. extra load which 

ennlil have lirrn cnrrii-d. 



= % excess power 



h' 100 

- rr-r-. 
A available 

e\i-ess X 100 

= % excess lifting capacity. 



A^ nvniliililr 

Tin si \ ilues as well as the speed ranges, can be ob- 
imd easilx for se\eral combinations of section and area 
superposing polar curves and the diagram, several 
amples of which an ^i\en lati-r. 

It is i\id'-nt that the above excesses arc the horizontal 
--rtieal inten-epts between the selection curve nnd 
e polar curve and when these excesses are ero we have 
e limits of Hight range. 

\\ . can at once proeecd to illustrate the melli.nl by an 
ample : 

Let U wi j.;ht of maehiiie complete with load 2500 

III' 120. available with variable efficiency. 

niiig various values for V we can tabulate values 
r K, and K, for values of S. Let us try 250, 350 and 
sq. ft. Then plot the curves of A"/- in function of A', 
ritini; on the eurves the velocities for which these eoeffi- 
nts occur. This will be our wing selection diagram. 
A CIITM- in the example is also given for .S5O sq. ft. 
id HUM) Ibs. to stimulate empty gas tanks, in order to 
ow the conditions of flight when the machine is light. 
The peculiar waves in these eurves are due to the 
riable efficiency assumed for the jMiwer plant. \Ve know 
at this varies from zero when the machine is standing 
ill to .1 maximum value when the machine is going near 
highest s|K*ed. and then decreases again. If the effi- 
ney was constant these curves would IH- of the simple 
i: 

\ ri '... + r which it a parabola. 

The tabulation and diagram follow: 

= Assumed efficiency of power plant 
/// X K = Power available. 

The values in the following tabulation can be obtained 
cans of a slide rule or by the use of the accompanying 
kits. 



V K H.P.X. F 



IM 



MM 

4.MO 






ZU.M 

. 



.. .. 

: 

. - .. 



n 

S 



744 

nc 



HI 



i 



84. Ft. 
K 



For 4WS 

l.lhl 
V K 



J 
40 

n 

- 


11" 







' 

. 
.-Mil 





v 

.mm 





- 

.0004T7 



M 
n 
7* 



II* 

. 




The above tabulation could be further improved by 
letting the weight change for each value of area, as would 
be the cise in practice. The effect of this would In- to 
bring closer together the ordinates of points on the dia- 
gram. 

us provide ourselves with polar curves of the wing 
sections that we wish to consider and draw them up to 
the same stale as the diagram. For ease of inspection, 
either the |ilars or the diagram should IK- on transparent 
paper so that we may place one over the other and still 
see both. To supply the example. \ polars of to-day'* 
most fashionable curtcs are herewith presented with the 
selection diagram superposed. 

With the alovc material at hand we can now proceed 
to select our wing. The observations can be tabulated as 
follows: 

T 



La* 






J 



274 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



READINGS FROM WING SECTION DIAGRAM 



READINGS PROM WING SECTION DIAGRAM 



Section 


Area 


High Sp'd 


Low Sp'd 


Best Glide 


Excess Power Section 


Area 


IIU-h S|,M 


Low Sp'd 


Host Glide 


E\r< ss 1'ow 






V i 


V i 


V i Gd. % 


V i % 




V i 


V i 


V iGd. % 


V i % 


R. A. F., 
No. 6. 


250 
350F 
350L 
450 


83 314 

77 214 
77 114 
Tl.r, I'.. 


56.6 15% 
48.3 16 
42.2 17 
42 16 


60.5 8V t 12.5 
56.5 7% 11.75 
49.5 7V4 11.75 
53 6 11.1 


65 8Vi 22.2 
54 814 32 Eiffel 
47.5 8% 51 No. 36 
48 8 39 


250 
350 F 
350 L 
450 


85 2% 
79 1 
80 -14 
74 1 


59 1214 
4SIL- 14 
41% 16 
42.7 14 


72 5 13.1 
73 5 12. 
54 5 12. 
56 4.5 11.25 


69 7 15 
72 5 22 
51 5% 47 
53 614 35 


Eiffel 
No. 32 


250 
350F 
350L 
T-0 


Sli 1 -- 
83 3 

87 iy 

8T 2 


61 1314 
50 15 
43 17" 
44 15 


77 6 13. 
65 6 11.75 
55.5 6 11.75 
59 514 11. 


75 7 15 
63 614 27.3 Eiffel 
55 6% 47.4 No. 38 
55 614 35 


250 
350F 
:J5UL 
450 


85 214 
80 1 

83 -V4 
77 


57 13 
47.5 14 
43 16 
42 14 


67 6% 12.25 
56 6% 11.25 
49.5 614 11.25 
52 5% 10.62 


67 7 23 
56 7 34 

19 7 52 
50 6% 40 













: 4 



' .'_/4iH 
jyn ' 






POCAR CURVE FOR 
5ECTION N3Z (EIFFEL) 
t Unrft m lb. pr s<^. 

'>* aos. Mumencal .041 



:L:ig 








. 







. 




POLAR CU 


... .., 


7 




i SECTION N9 


3S 


// 
/;, 


' i 


Unitj , n Ib 


-m 




j it pfti- mi. 


-W/r 


j ' 


- TRANSLATION 


I 




S'je 2.08. Him 

j_| 




' -I ri.iir nj_ 


i ;- i:-- ; d .- J - 1 - 









S P0f 3l. 



;: POLAR CURVE FOB 
SECTION N38(EIFFEL) 

Units IB Ib5. per J<j. 
ft. pftf. hii. p.hr. 



. Units m ibs. pe 
ft. p^. nil. p. hr. 




MKTIIOI) OF SKLKCTION 



AN .\I.KO1M..\.\K \V1.\(, 



Tin- selection can now In- made according to the results 
desired with proper regard for tin- slrinlur.il ijunlitu s ,.! 
tin- sections. \\ e will thus ha\e selected, in a sure way. 
tin- liest wing for our pnrposr. .-mil a performance curve 
can now In- ilrawn. This iiM-tlioil cnahlcs us to visualise 
the cll'cct of chances in the \-iriou-. factors. MS follows: 
1. Since K,. is not ill penili nt on /', equal velocities at- 
ainalile with \arious H.I'., for a i;ivcn area and weight, 
will lie on the same horizontal line. i.e.. if our powi r is 
the alicissac will vary proportionately 

A iloi s not ilepenil on /(' ei|iial velocities |nr 
area and power will lie on the same vertical for 
nil \alues of \V, i.e., if our weight is changed the ordi- 
i.-ites will vary proportionally. 



S. A Ungrnt drawn to polar from the origin of the 

diagram will show |.\ its point of cont-i.t tin \ n luc of 

INI nli nee for the l>est j-lulin^ nn^le, on the snine hortxontal 

i.l Ih. , ..rri -spoiidiiiu spin), (he slope i{i\es the value 

of the Ix-st ^liiiing gradient. 

I Tin httle diagram in the lower part shown how 
parasiti resistance ciils down the spied and CXCTM |n>wer 
and its nlati\e importance on m-iclum s of largr and Miiall 
area. 

The accuracy of the |M-rform.ince pr si d \>\ this 

method d.-p. mU on the accuracy with which the head 
resistance, power avnilaltle anil the currection factors II.-IM- 
l>een determined. The accurate selection of each one of 
thcuc presents a prohlem hy it- It 



CHAPTER VII 



NOMOGRAPHIC CHARTS FOR THE AERIAL PROPELLER 

Bv S. E. SLOCUM, Pn.D., 
Professor of Applied Mechanics, University of Cincinnati; Member S. A. E. 



In discussing propeller performance it has been cus- 
tomary to assume that the power absorbed by the pro- 
peller varies as N*D r> , and that the thrust varies as N 2 D*, 
where N denotes the propeller speed in revolutions per 
minute or per second, and D is its diameter. These as- 
sumptions, however, are only true for an ideal propeller; 
that is, one which is perfectly rigid and perfectly sym- 
metrical. For a propeller as actually constructed, the 
law governing power and thrust may differ materially 
from the above theoretical assumptions. The actual laws 
governing propeller thrust and power for a particular 
propeller were developed directly from experimental data 
obtained by M. Eiffel and Captain Dorand, without mak- 
ing any theoretical assumptions whatever, the method em- 
ployed being the standard process for the adjustment of 
observations by the method of Least Squares. The re- 
sults showed that the performance of a given propeller 
may differ materially from that prescribed by theory for 
an ideal propeller, and also showed how experimental data 
on propellers may be analyzed on its own merits, inde- 
pendently of all dynamical assumptions. 

As long as the whole subject of propeller performance 
was in the experimental stage, it was doubtless wise to 
base all calculations on the assumption of an ideal, pro- 
peller, as it gave a certain uniformity to results. At pres- 
ent, however, when propeller types are becoming stand- 
ardized, it certainly permits of greater refinement in de- 
sign to determine by experiment the characteristics of 
the standard types of propeller adopted. This is the 
method followed in all lines of engineering. For instance, 
the performance of aviation motors is determined for a 
given type of motor by actual test of this type and not 
solely from the principles of thermodynamics, while as 
another example, the firing data for a long-range gun 
are based on experiments made on this particular type of 
gun and not on the ideal assumptions of a perfect pro- 
jectile fired in vacuo. 

Of course it cannot be expected that general formulas 
for thrust and power can be derived which will apply uni- 
versally to all types of propellers, any more than that a 
gas engine power formula can be derived which will apply 
accurately to all types of motors. It is perfectly pos- 
sible, however, to derive formulas by the method men- 
tioned above which will apply accurately to a given type 
of propeller, which will assist materially in the problem 
of powering aircraft, that is, in determining the most 
effective combination of motor and propeller for a given 
wing and fuselage assembly. 

The formulas so obtained, however, are exponential, and 
consequently somewhat difficult to use in their algebraic 
form. To represent graphically the various combinations 

276 



of quantities involved, M. Eiffel devised what he called 

Polar Logarithmic Diagrams," which constitute, in fact, 
a very ingenious and practical application of vector al- 
gebra. But the application, as well as the theory of these 
diagrams, is rather complicated, while the results depend 
in part at least on determining the intersection of lines 
which meet at an acute angle, and such points of inter- 
section are liable to a considerable error when determined 
graphically. 

There has recently come into use another means for 
the graphical solution of exponential formulas which is 
similar in principle to that devised by M. Eiffel in that 
it depends on the reduction of an exponential to a linear 
form by the use of logarithms, and the employment of 
logarithmic scales. This device consists in the construc- 
tion of diagrams called nomographic charts, or alignment 
charts, from which the required results may be obtained 
by simply connecting the points representing the given 
data by straight lines, and then reading off the intercepts 
on the proper scale, the method being similar to that of 
using a slide rule. 

In Plates I and II accompanying this article, no >- 
graphic charts are shown which represent the formulas 
for thrust and power of the aerial propeller as previously 
derived by the writer in the references given above. 
These charts, of course, are not universal, as they simply 
represent the performance of a particular propeller, but 
similar charts differing only very slightly from these 
may be constructed for any standard type of propeller, 
and their use will facilitate calculations on this propeller 
to the same extent that the use of the ordinary slide rule 
simplifies arithmetical calculations. 

It may be noted that the effect of varying the ex- 
ponents of N and D will be to move the intersection axes 
slightly to one side. For instance, if we follow the 
theoretical assumption that the thrust varies as A' J 7) 4 , 
the intersection axis on the thrust chart will be moved 
slightly to the right of the position shown; while sim- 
ilarly on the power chart, the assumption of N 3 D' > will 
also move the intersection axis slightly to the right. Like- 
wise any change in the quadratic terms involved in these 
formulas will affect the relative location of the points on 

V 

the scale giving the ratio , and in this way change the 

ND 

readings on the horsepower and thrust scales. Except for 
such shifting of the intersection axes and changes in the 
graduation of the various scales, the nomographic charts 
will be exactly similar in form for all types of propellersj 
Having determined the thrust and power for a given 
propeller, the torque and efficiency are easily found. Thus 



DIAMET 

Fee 
PROPELLOR SPEED N 


ER D 
t 
* 

J 
-4 


7 
4 

bx 


Eumpl* of .,.|.lir.uon of rh.rt. SnppOM 
X (t |.ro|*ll,r Ml X = 1400 r p m. mtt 

130 fl w. Tba = .60 

O Draw line Joining UM point D - H oith 
UM IntorMcUon *>U In Uw point A .li.in i 

$ lot = .60. Tb IntcTMrtlon of Ihw I 

M' 
Kl (im 300 II I* |.|.ruiinu>ly. p 

ki 

HORSC POWER 

s 

-to 
-30 

fa 
-_ ^^^ 

A JOO 
4OO 

POWER 

/oo FOR 

AERIAL P 


t iliimrirr I> 
,|i.., lini-ar vrlocity V = 

Hi.' iMiint N - 36. rullinc 
u- ,...,,,! A with tin- |Kilnt 

nr with thr bone powrr 

ATI jTO 

-1.00 

-AS 

-JOO 

-Jf 

-.70 
-J0f 

-40 

CHART 

THE 

=OPELLOR 


M- 


/wo 

/700 

AMU 
-/o 


14- 

XJt- 

Zl- 


/JJO\ 
'JOO >y 


It- 
11- 


\ 
//jo X 

-/OJO \^ 

/too 
9SO 


a- 


-esif 
1 O, 
-too 

-ISO 
-700 
-6SO 


NOMOGRAPH OF THE FORMU 

- t , O76 *-** J". /S f -\r /\f 

Rfi. ip- N D ri + *4X.- 


LA 

f] 

cum. 


7S6 SSO 


-5.ET.5lo 








DIAMETE 
Ft 

PROPELLOR SPEED N 
Rcv./5*c Re^MIn 


R D 
et 

p 

s 

s 
6 

1 

II 
~ut 


THRU5T CHART 

FOR THE 

AERIAL PROPELLOR 


NOMOGRAPH OF THE FORMULA 


jt 

*7- 




-/7J-0 
-I7OO 

-tffo 
-/too 

-/.WO 


Z ' 30,000 L VNW J 

g 

^ RAT 


or 
u 

h TMRUiT 
Z Pounds 
10 

-90 

-4O 

-100 

~ 4-OO 

ZIOOO 

4000 
^-JOOO 
^-4000 

Hj2. E./OOSO 

Ezcmpw of pplication of chart. Oirn D = 8 ft, N = 1500 r.p.m. = I 
V SS ft . Join th |Kint D = to UM point N - 35, rutlm 

t B. Join B to UM point = .60. Th Inur-clion of thl II 
ND 
UM tbruit teal* cie F = TOO lb>. 

5. &.olo< 


jfe 

-JO 

Jl 
-40 

-.70 
-60 

^*** 

ti r r 
hi- n 

r with 

um. 



*.!- 
*/- 


-1*30 \. 


/- 

/7- 
/- 


-lisa 

-1100 \ 

\ 

-ioso X 

-/ooo 

-*JO 


/J- 

/a- 
//- 
/o 


-AM 
-400 

-WO 
-700 

600 



277 



PROPELLOR TORQUE T 




-SPEED N Ft.Lbs. THRUST F 


LINEAR VELOCITY V 


o c ' 


Lba. 


Fi/'Sec. 


<o 




IO 


O /0 




1 1 


HORSE POWER 


_ 


X. 




cr a: 




/O 


2.0. 






rn -if.1,-1 " 












oo 


40 







30 


o 


EFFICIENCY 




~ -E 




20 


E" 1 * 


y Jte- 


Per Cent. 




^ 






=- 


O 




/o 


X.S 


^AFOO /oo 




30 


=2 


U. 








- ^\^ 




40 


^/OO 


U JO- 




- 




^X^ ,JOO 




SO 


- 






zo 




^ 300 




=- 


Zoo 


40- 




- 


*2 


^x^ 40O 







300 






r Q 








^^/oo 





SO 








>4Op 






400 









- 


^s 






^--5-00 


60 




40 


- 


,000^= 


^Ss 




B^ 


70 




SO 








~ 


EE ~""T^^^^ 


C o 




60 














~"==^ _____ 




70 




- 




.300 




~--~^^ /oo 




30 
SO 


/S 


fZOOO 




_ 




4-00 


^000 


^~^y/o^ 




/oo 




3000 




- _ 


_ 


/i*=> 




_ 


-*ooo 






30OO 


/30- 
/40- 






JOOO-^ 






4000 


/SO 







z= 




= tooo 


=- 


- 






/Mao = 




Er- 


^oo- 






Ann 


=/0 ooo 


ZX.O 




Example of application of chart. 1. Given N = 1500 r.p.m., H.P. := 


SUPPLEMENTARY CHART 


200. Join these points. Intersection of this line with torque scale gives 
torque = 700 ft. Ibs. 2. Given thrust = 700 Ibs., lin. vel. = 120 ft /sec 
H.P. = 200. Join P = 700 with V = 120. intersecting efficiency axis in 
point C. Join this point C with H.P. = 200, and prolong to intersect 
efficiency scale giving efficiency = 78%. 


FOR 

TORQUE AND EFFICIENCY 

Rrf 5 

O ' -5.E.^Jocum. 




Application of Chart. Given D = 8 ; N = 1500 
r.i>.m.; V = 90 sec./hr. Construction shown, as 
explained on Plates 1, 2 and 3, gives H.P = 180; 
P = 590 Ibs. ; T = 650 ft. Ibs. ; Eff. = 76%. 



h 

"0 




=v 0,000 



COMPLETE NOMOGRAPHIC CHART 

Firf 4. FOR THE 

AERIAL PROPELLOR 



278 



NO.MOC.KAIMIU CHANTS 1(>K Till. \l K1AI. 1'IJOI'I I I IK 



.111(1 



I,.,,. 



\ 



ilwork I \. 



Klliclcnev = 



: work .'.:>o h.p. 

whin /' (Iciiiiti-s tin- |ini|irlliT thrust, .-mil /' is tin- s|M-cd 
of tin- plain-, or r.-l.itm M locity of tin- wind witli r 
to tin- propt-llrr. To make tin <;raphic.-il solution com 
pli-tr, howcicr. DOmOgraphiC chart-, nriy also In 
stnicticl tu i;i\c tori|in anil i th'cicncy . as shown on Plate- 
Ill. 

These charts art- presented separately in Plates I, II 
-iii.l III tor tin sake of rh arm-is, and an example of 
their use i-- shown on each. 

I or jiru-tii-al purposes it is more eonvrnirnt to put all 
tin- . Inrts on oni- slu'i-t. as shown on Plate I\ . As an 
i-xaniph- of its use it may Ix- well to follow through the 
ron>' rurti. in shown on Plate IV. In this example we are 



uiv.ii pni|H-llrr ili.-iiiii-ter I) = 8 ft., pn.pt Her speed 
AT=;I.,iiii r |, I,, j :, r.p.s.; linear sprrd /' = 9O miles 
|MT hour l.ij ft |H r Mft 1 irst join \ l.'.tMl with 
D=K, flitting power axis in A and thrust axis in It. 

I I 

BteH =.66, join . I with this | M iiiit on the .scale 

\l> M> 

for powi-r. Tin iiitim |<t of this lim with the |K)Wer scale 

li.p. 18(1. \r\t join H witli the point .tili on the 

/ 
scale for thrust. The intercept of tins Inn with the 

\/) 

thrust -, Thrust A' .">!> Ihs. Now join h p. = 180 

with .V ---- I.MMI. Tin- intercept of this line with the torque 
scale gives Torque T = 630 ft. Ibs. Lastly, join the 
point Thrust f=S90 with the point / on the 

velocity scale, cutting the ilicn-ncy axis in tin- point ('. 
.loin this point (' with the point h.p. I HI). The int. r 
i-ept of this line with the efficiency scale gives Effi- 
ciency = 76 per cent 



CHAPTER VIII 



METHODS USED IN FINDING FUSELAGE STRESSES 

BY J. A. ROCHE, M. E., Aeronautical Eng., U. S. A. 



Reasoning Leading to Choice of Criterion and Methods 

Used in Finding Stresses 

An aeroplane fuselage is a structure whose function 
is to connect the wings, landing gear and tail surface, 
of the machine; hold them in their proper respect, 
locations and transmit the stresses which hold the machine 
in equilibrium, in the air and on the ground from ea< 
one of these parts to the others. Its secondary function 
is, of course, to house the engine, aviator and accessor.es 
While in the air, the fuselage transmits from the tail 
planes to the wings moments which are necessary 
give stability or to neutralize whatever couples may 
exist due to center of pressure and thrust line locahon. 

In normal flight, the stresses due to these momenl 
are slight, but in exceptional cases such as in recovenng 
from a vertical dive, these moments and the 
thev cause are large. 

It may seem at first that these can reach enormous 
values if the recovery be made very sharply by raising 
the elevators at a high angle, while traveling at a high 

rate of speed. 

It has been measured that a man in the pilots seat 
can exert a push or a pull force of about 250 pounds. 
With the leverage of a standard " Dep." control, the 
force that can be exerted on the control cables is about 
600 pounds and this can bring about a reaction of 400 
to 500 pounds on the elevators according to their shape, 
on which depends the position of the center of pressure 
behind the hinge. 

The resultant of these two forces is as shown by the 
above figure, and this resultant can be used as a basis 
for a stress diagram of the rear end of the structure. 

The stress diagram yielded is of the simple usual type. 
Usually no attention is paid to stresses in the rear end 
of the fuselage caused by landing shock and the front end 
is analyzed by itself in a rather crude manner. 

The object of the following is to investigate the latter 
condition as thoroughly as possible, taking into account, 

Location of landing gear, 

Location of center of gravity, 

Inertia forces, 

Point of application of all loads. 

As a machine runs along the ground in normal position, 



the reaction force applied at the wheels, being equal 
and coincident with the resultant of the loads and inert,; 
forces, must pass through the axis of the wheels and also 
through the center of gravity of the machine, 
not strictly true, because other forces may be at pis 
helping the machine, namely: airloads on the mam pis 
and other surfaces; however, it would be fair to assume 
that the roughness of the ground produced a force equal 
to the inertia forces. If the rolling friction is very high 
and the machine has a tendency to turn her nose, the t 
air loads must act down to keep the machine in equil.bm 
whereas if the rolling friction is too low the tail air loads 
must act up to keep the machine rolling on her wheels 

In the latter case, the machine will have a tendency 
to porpoise; in the former, it will have a tendency 1 
nose over, but it seems that if the wheels are so local 
that the resultant of the weight reaction and rolling 
friction passes through the center of gravity, the aeroplane 
will then be stable as it strikes or rolls on the ground. 
It is true that the rolling friction is a very variable 
factor, but it certainly has a mean value and we cai 
assume that the inertia of rotation of the aeroplane will 
take care of most variations from this mean value of 
rolling friction. 

It is not advisable to assume the machine landing wit 
a perfect " pancake " and striking with wheels and skid 
together, for this is neither the worst nor the usual con- 
dition of landing. It is preferable to assume the machine 
landing on its wheels only in normal horizontal position 
and with tail planes neutral, which is a fair mean between 
the possible conditions mentioned above. 

The stresses found can be those due to the normal 
loads taking no account of shock ; and since shock would 
not alter the direction of the forces but only their magni- 
tude, the stresses for any condition of shock can IK- 
obtained later by applying a proper constant to the normal 
stresses or by changing the scale of the stress diagram. 
The work can be performed according to the following 

plan: 

1. Draw to scale the fuselage under consideration and 
mark on it the centers of gravity of the various loads 





280 



MKTHODS I'SKl) IN FIXDIXt; 1 1 SKI .\(. I. STRESSES 



281 



which it must carrx : label r;ich one with it-, n r 
weight. Discompose each one of these loads .mil apply 
propi-r share to each oin- of tin joints on whirh r 

I. Draw \i rlical and hori/ontal fiinirulnr polygons or 
two polygons at an angh to ,- ich olhrr. The intrrsr.-lioii 
of tlu-ir resultants gi\es tin- position of tin- << nl 
gr.iv ity of tin system. 

Draw reaction force passing thro< Mills found 

and center of axh . make all load Motors parallel to it. 
J. Draw stress diagram, closure will In- considered as 
l-hrrk on the work. 

i rach inrinlirr according to tin- stress it carries, 
taking bending or Ir.inswrse for,, , hitii account. I ..r 
tin- portion of a strut In-low the point of application 
of the load add to (In- direct stress shown by the stress 
n tin portion of that load which had been consul 
ere, I .-is applied at 'In- lower end. For the upper portion, 
deduct the portion of the load which had been consul, re, I 
pplied to the upper < nd. 

It was admitted in step 5 that the stress diagram 
was not the final operation in finding the close value of 
strr ~,, - in the members of the fuselage. This is due to 
ict that this truss is loaded internally. Before 
starting to draw the diagram the forces ha\e been dis 
Composed in a definite way. we must now correct for the 
effect of this assumption which had made possible the 
construction of the stress diagram. 

Step ." indicates bow the proper correction is made 
for the stresses in the vertical struts. The reason and 
method are ob\ ions. A similar correction should also l>e 
applied in the hori/ontal members. It is clear that the 
various pin points sustaining a load will partake of the 
hori/.ontal component of the force due to the inertia of 
that load. Not necessarily in the inverse ratio of their 
distanci s from that load, but in a way depending on the 
riifidity of the members through which this load is con- 
'I to them. 

Thus, instead of having: 



The resultant!! of these systems are equal in all re- 
spects; but tin- second, more correct assumption would 
cause a more complicated str. s- di IUT.IIII. which would 
not show \irv different stresses in the longeron*. It 
seems ijnite proper to make these corrections afterwards 
if they are desired at all, when the m< tubers havi 
.ned and their degree of rigidity is known. 

In the ease of ohlicjiie members, both a vertical and 
hori/ontal correction must be applied. Tims, in spite 
of the efforts of this method to give close accuracy, there 
is still room for the engineer to make sunn- corrections 
baaed on good judgment, but these corrections mid not 
IM- made in most ordinary canes. 

The present example illustrates the application of 
the method proposed here, a small variable angle of inei- 
ih in e biplane being assumed. The apportioning of loads 
to pin points is done as follows: 
(I) KntfiHf and Vroprllrr I Hi Ibs. 

This load will be considered us applied at the vertex 
of a small triangular truss which is in fact supplied 
by the engine crankcase. Thus: 




(2) Tank,, Fuel and Oil. 

' 7 




Here joint a must take 



I 

20 X U 



14.3 Ibs. 



14 

SOX 4 
b must take - =5.7 Ibs. 

(3) H'hrelt * t Ibs. 

These rest direetlv on the ground and impose no stresses 
If strut a was elastic and strut 6 rigid we would have: . . 

(i) H'inffi l-.'.'i Ibs. 

As in the ease of the power pant, these are taken as 
concentrated at the joints of their Mip|>orting truss. 



a 



f 



/ 



(3) Pilot 160 Ibs. 

1 1 ;r, + 0.3 n\ 10 ;r, 1 1.3 n\ = o 



These moment equations show that we have an indeter- 
minate case as could be expected, since there is more 
than 3 points of support, all we can do ' to eliminate 
one of the terms in a judicious manner. 



282 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



14'-*- 




By setting for example 

W l =W 2 X 16/14 

We have then three equations containing 3 unknowns, 
as follows: 

(1) 14 X 16 rF t + 9.5 W 3 16 W 2 11.5 = 

14 

(2) 6V 16 W z + 6W 2 16W 3 15W 4 = Q 

14 

(3) W, 16/14 + JV 2 + W s + W t = 160 

~OW 2 9.5 W s 1 1.5 W 4 = 
12.685 Wv 16 W s 15 W t = 
2.142 W 2 + W 3 +W 4 = 160 



+ 9.5 11.5 
16 15 
16 1 1 

9.5 11.5 

12.685 16 15 
2.142 1 1 



22800 29400 



52200 



~- 53.8 Ibs. 



146 305 123 90.9 



16 X 53.8 
- 



= 61.5 Ibs. 



Check 



11.5 

12.68 15 

2.142 160 1 

96.9 



32.15 23300 



96.9 



. = 24.1 libs. 



9.5 

12.68 16 

2.142 1 160 19250 



96.9 



96.9 



= 19.9 Ibs. 



19.9 = Wi 
24.1 = W a 
61.5 = JPPj 

53.8 = W 2 
Total 159.3 




HORIZQNTHL FuNICULRR PoLV&ON 

-.OCATINb CcMTEKOr M/133 or AfROPLflNF 



;. 1 . 



LOADING DIAGRAM 

Srrixv> location of M*t (xJI)rd(rfd 
In Sir, u fUnft. 



IH A HOfttZONTAL I INC 



SCRLE OF DIMENSIONS i l* = 20" 

FORCE SC/JLE |" = 100 Ibs 



/ 




VERTICBL FUNICUIBR PotxcoN 

Locflrtnft CENTER OF MAIS or ACROPLANC 
IN A ICRTItni lIMe ^ ^ 

SCALE or DIMENSIONS : I -.- ZO 
FORCE JCRLE: = lOOlbJ. 

J..f>Mhc M.C. C U- '. 




STRESS 

SHOWING LOCATION am 

Or GrlftvlIY 
Rt5utTNT REACTION 

STRESSES m ncnaeicj 
DIMENSION Sem.i.-r=2o w 
FORCE SCflUE : |"=IM i 







MKTHODS I SKI) IN I 1M)1\(, 1 I SKI \(. I. STKKSM S 



288 



(6) Tall H'orkt 3() 11.-. 




7" 



_L 



At tlii-. point it is interesting to study the retarding 
cll'cct of the rolling friction which lias been assumed. 
This force as scaled from the diagram is 

F= 1 IT ll.s. 

FMa 



since 



and 



~T~ i 



~~ ~ 15 - 8 



mass 



/' 1 1 A 

Hetardation o = = ^ = 9.3 
./ 147 



i 

also a = = . 
a 



= p = 9.8 

rfi 

and J f </t = J U.S </ 



Integrating we get -- h c = U.S -j- c 



to <li li riiiiin tin \alne nf r we know that 
in the case of a landing made at l<> in.p.h. at the instant 
of first contact with the ground: 

V = 58.6 ft./sec. 
and 5 = 

then - = c=17*0 

and when the aeroplane has finally come to the V = O 
and 



and this figure is not an improhahle one for the machine 
n question, anil shows a capacity on the part of the 
landing gcnr to take care of rather rough ground without 
causing the machine to turn on its nose. If this figure 
u : > checked on the nYld. it would prove that the rolling 
friction has been correctly assumed. 



CHAPTER IX 



THEORY OF FLIGHT 

This elementary and clear definition of the principles of flight was prepared by the Aeroplane Engineering De- 
partment of the V S. Army, from lectures delivered at the Army School of Military Aeronautics at the Ohio State 
University. These lectures were given by Messrs. H. C. Lord, G. T. Standard, and W. A. Kmght. 

Investigating wind action - Constant values - Studying action of wind - Streamline shapes -Head resistance - 
Liff drift Md angle of attack - Suction on top of plane - Center of pressure - Cambered planes - Horizontal 
flight Engine power Power to climb Stability. 



In this age of mechanical flight everyone is interested 
in aeroplanes. But very few people, however, clearly 
grasp the underlying principles. The theory involved, 
nevertheless, may be demonstrated by simple experiments, 
so that the reader with only an elementary knowledge of 
mathematics and mechanics can understand. 

The simplest principle of aeroplane flight may be dem- 
onstrated by plunging the hand in water and trying to 
move it horizontally, after first slightly inclining the palm 
so as to meet, or attack, the fluid at a small angle. It 
will be noticed at once that although the hand remains 
very nearly horizontal, and though it is moved hori- 
zontally, the water exerts upon it a certain amount of 
pressure directed nearly vertically upwards and tending 
to lift the hand. This is a fair analogy to the principle 
underlying the flight of an aeroplane. 

The wings of the plane are set at a small angle, and 
the plane is pushed or pulled through the air by the pro- 
peller, which receives its power from the engine. The 
action of the air on the wings, inclined at an angle, tends 
to lift the plane just as the action of the water on the hand, 
inclined at a small angle, has a tendency to raise the hand 
out of the water. 

Investigating Wind Action 

A rough form of apparatus for studying laws of wind 
resistance is shown in Fig. 1. The arm E hinged at C 
carries a rectangular plane B. The adjustable weight D, 
supported by the arm F, is used to balance the pressure 
of the wind from the blower A. The pressure exerted on 
the plane B can then be measured by moving the weight D 
along the arm F until B floats with the wind. 

Professor Langley, in another experiment, proved that 
we can investigate the action of the wind upon various 
forms of surfaces as well by directing a current of air 
of known velocity against the surface held in position, 
and weighing the reactions, as we can by forcing the 
plane itself through still air. The special apparatus used 
was mounted on the end of a revolving arm driven by a 
steam engine as is shown in Fig. 2. The chronograph, 
a recording instrument, was used to measure the velocity 
or number of revolutions of. the table in a given time. 

By such a method as that shown in Fig. 1, and that of 
Professor Langley, it is easy to see that the laws of pres- 



sure and velocity can be determined readily. Methods 
such as these have been used in determining that the iciiiil 
resistance varies as the square of the velocity. 

In other words, if the velocity is doubled it follows that 
the resistance is increased four times, or if velocity is five 
times as great, the wind resistance is twenty-five times as 
large. 




FIG. 1 Elementary apparatus for studying laws of wind re- 
sistance 

Constant Values 

It would therefore seem to need no experimentation to 
prove that if we increase the surface B (Fig. 1) we would 
increase the pressure in direct proportion to the increase 
in surface area. Now if we were to increase both the 
velocity and the area of surface, we would increase the 
pressure proportionally to the product of the square of 
the velocity and the area of the surface. Thus if we 
were to raise the velocity of the air three times, the re- 
sistance would be increased nine times, and if we then 
doubled the surface we would double the resistance, which 
has already been increased nine times, making a total in- 
crease of eighteenfold. 

There is still another factor to take into consideration 
in calculating wind pressures, and that is the shape of the 
surface. To take that into account we must use what is 
called a constant, the value of which is determined by 
experiments for each particular shape of surface. 



284 



THKOHY OF KI.K.II I 








- 1'rof. I.murlry's apparatus for invi-stijratinjr wind ac- 
tion on various forms of sun 

Tin- following explanation will enable one to see very 
l.-arlv tin- meaning of the term constant and bow its 
able i-- determined. First let us explain the term formula 
which is merely :i si-ntence tersely expressed. To attempt 

make a study of flight without formulte would make it 

iry to express relations between <|uantities in long 
Mragraphs of words that could more readily be stated in 
iiniple equations. Thus if it were desired to state the 
ule that the quantity A multiplied by twiee the quantity 

1 i- i qua! to ('. the formula representing this would be: 

AX 2B = C 

Jach letter or symbol in a formula represents some factor 
hat is substituted when its value is known. If A = 16, 
:nd H= I, then ('=128, since the rule interpreted 
eads: Hi X 8= 128. 

Derived and empirical n/iiatiom. The term equation 
imply means that the quantities on one side of the equal 
iliii are equivalent or equal to the quantities on the other 
iide. Equation* are of two kinds, derived and empirical. 
\ derived equation is susceptible to proof, by use of mathe- 
natical processes. An empirical equation is neither de- 
ivcd nor proven. It is merely a .statement of the results 
f experiment regardless of mathematical proof. 

In many branches of engineering, empirical formula- arc 

onstantly used, and in aviation the lack of a satisfactory 

u-ory of air flow makes empirical formula? based on 

xperimeiit most necessary. Kmpirical formula- are really 

mental averages. 



Tin i. mi . "iiitant can now be fully explained and it 
will In Men IIOH Ix-autifully it works out in a formula. 
It is often found necessary, especially in an rx|M-riiin ntal 
tit Id. to introduce numerical constants to balance the two 
sides of nn equation. For example, the pressure on a sur- 



1 PROJECTED 




In. I - Illustrating 



of term " projrctr<l area " 



face, as we have already learned, is equal to a constant 
times the projected area of the surface (see Fig. .S) times 
velocity squar<il, or expressing the .same quantities in a 
formula, 

P = KSV 

where l> = Pressure S= Projected surface area 

K = Constant V 1 = Velocity squared 

The exact value of the constant K for any surface is 
determined experimentally by wind tunnel tests. So val- 
uable have wind tunnels proven for s i.-h determinations 
that several of the large aeroplane builders now have in- 
stalled them in their plants. 

In solving a problem it might ! known that the pres- 
sure I' \aries as the area of the surface and the velocity 
squared, but we could not express this relation in an 
equation capable of solution until a numerical value for 
K is determined for the particular sha|H- subjected to Un- 
wind pressure, such as the shape illustrated in Fig. S. 
Kach different shape of surface requires a different value 
for K, which can be determined cxjx rimcntally. 

The majority of formula- for air pressures involve con- 
stants, and the great advance in designing during the past 
two years may lie traced directly to the determinations by 
the aerodynamic laboratories, of better values of these 
constants, for use in empirical formula-. So when M. 
F.iffcl, or other men of authority, inform us that the con- 
stant K for a flat shape is .<><);(, we accept the value just 
as we do the report of a chemist who tells us the compo- 
sition of an alloy. 

Parasite Resistance 

A picture of a typical aeroplane is shown in Fig. 5. 
Notice that all the struts, wires, landing wheels and tin- 
fuselage or body offer resistance to passage through the 
air a resistance which must be overcome by the engine. 
The sum total of the separate resistances of all these 




I i'.. V K\|M-rim<*n 



HIT lift of inclined 
rrnt 



Mirfnrr in air cur- 



286 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 




H 



FIG. 5 Curtiss aeroplane, showing control surfaces 



parts is called the parasite resistance. This wastes power 
and so all such parts are carefully streamlined wherever 
possible. 

Note the wings or aerofoils, two on each side, one above 
and one below, and at the rear a vertical rudder R in 
front of which is a vertical fin V, and the horizontal fin 
H, the back part of which can be turned up or down by 
the pilot. The effect of this is to cause the machine to 
point up or down and thus change the angle at which the 
relative wind strikes the aerofoils. This change, as we 
will see, has much to do with the flying of the machine. 

Lift, Drift and Angle of Attack 

Thus far we have found a lot of things about an aero- 
plane which would tend to prevent its flying. Now let 
us study Fig. 4. Here we have a plane B fastened so 
that it makes a small angle with the direction of the wind 
from the blower A. The arm is hinged at C, and bal- 
anced by the weight D, so that when the movable weight 
W is pushed back to C the plane B will be slightly too 
heavy. When the blower A is started the plane B in- 
stantly lifts and the amount of this lift may be measured 
by the movable weight W. If we replaced this model 




Fio. 6 Illustrating how lift and drift result from the moving 
of an inclined surface in the direction of arrows 



by one exactly like it except that the plane B makes ; 
much smaller angle with the relative wind we would fine 
that the movable weight W would have to be much nearei 
C than before. This simple experiment proves the exist 
ence of a force which tends to lift the plane and furthei 
that this force is greater as the angle is increased. Tin; 
angle is called the angle of attack that the plane B make: 
with the air stream. The force which tends to raise th( 
plane is called the lift, and evidently its value must de' 
pend upon the profile of the plane, the velocity squared 
and the angle of attack. 

Besides the lift, there is another force which is dui 
to the plane's velocity through the air, called the drift 
This force is due to the fact that the plane itself offers 
resistance to forward motion through the air. In Fig. 6 
A represents a bubble of air, BC a plane moving in the 
direction of the arrows. Now evidently one of two tilings 
must happen. Either the plane must force the bubble 
of air down or the bubble of air must force the plane up, 
This resistance that the bubble of air offers to being dis- 
placed, as we have seen, depends upon the square of the 
velocity with which it is forced out of the way. The 
total resistance offered by the bubble to the movement oi 
the plane may be represented by the force P acting al 
right angles to the surface of the plane. The horizontal 
and vertical components of P are represented by D and L, 
respectively. 

If we were to let the air on the surface have its way. il 
would push the surface upwards in the direction of I 
and backwards in the direction of D at the same time. 

So we put weight on the surface, enough to overcome 
the force L, and then quite logically call this force thj 
lift. And for D, we push against it, with the thrust from 
a propeller, and we call D the drift. 

This simple explanation enables us at once to state the 
reason why flight in heavier-than-air machines is possible. 
By pushing the inclined surface into the air with a hori- 
zontal force D, we create a pressure on the surface equal 
to P, the force of which D is the horizontal component. 
But by doing so we have also created the other component 
L, which is a lifting force, capable of carrying weights 
into the air. 



THKOHV OF FLIGHT 



_'H7 




I'n.. ' \pparatiis proving existence (if lintli lift anil drift 

Consideration of tin's resolution into lift and drift at 
OIKT Indicate! that tin- characteristics to be sought for in 
a surface are great lift with a very small drift, so that 
for a minimum expenditure of power a maximum load 
carrying capacity is obtained. 

.lp /HI rut 11.1 nxi-d to prove fiiitence of lift and drift. 
An apparatus used to demonstrate the existence of these 
forces is shown in Fig. ~. The inclined plane B is fast- 
ened to the arm S hinged to the carriage C at the point 
F. The carriage rests on a glass plate I) and is shielded 
from the wind from the Mower II In the screen K. It 




I' I*.. s I >r\ ice for measuring comparative air pressures IHI 
upper and lower surfaces of an inclined plane 

u found that when the blower is started the plane B 
will lift and the carriage C moves slowly backward carry- 
ing the plane with it, thus proving the existence of lift 




and drift. The screen E is then removed and it is found 
that the carriage moves away very rapidly, thus showing 
the effect of the added head resistance due to the carriage 

Its, If. 

Suction on top of Plane 

Tin- Hat surface is seldom used for the aerofoils of an 
aeroplane. The following illustrations and explanation 
will help to show the reasons for not using it. 

The plane 1' (Fig. 8) has an opening at () connected 
to manometer M. while on the under side is a similar open- 
ing connected to the manometer X through the rubber tube 
T. When the blower is started the manometer .M shows 
.suction at the point O on the upper side of the plane and 
\ shows pressure on the under side of the plane. In 
other words, the plane is not only blown up, but it is 
sucked up as well. 

This is very effectively illustrated by n still simpler ex- 
periment. Fig. 9 shows the plane AB of heavy card- 
board to which is fastened a light strip of paper at the 
point A and left free at the point C. When the plain- 
is placed in a wind blowing in the direction of the arrows 
the paper is seen to be drawn up to the position AC' away 
from the plane AB. 

Experiments at Eiffel Laboratory. Fig. 10 shows the 
result of accurate measurements by M. F.iffel of the suc- 
tion on top of a plane and the pressure underneath. I-'ur- 




FIG. 9 Showing suction on top of inclined pi. UK- when exposed 
to wind current in direction of arrows 



^vast/re Curve kr 
iower Surfoce 



I'n.. 10 Pressure diagram of upper and lower surfaces of 
inclined plane 

thermore, F.iffel has shown by recent experiments that 
when the angle of incidence of a flat plane is low. the 
value of the suction on the upper surface is considerably 
more than that of the pressure on the under surface. 
Thus in this case it is the upper side of the plane which 
contributes most towards the creation of the lift, a func- 
tion increasing as the angle grows smaller. This fact 
shows that the profile of the upper surface of a plane li is 
as much, if not more, importance from the standpoint of 
the value of lift than that of the under surface. 

Center of Pressure 

In Fig. 1, it is evident that the wind's force on the 
plane B could be entirely replaced by a single force act- 
ing at the center of the plane. The fact that this point 
would In- the center of the plane is due to the fact that 
the wind strikes the plane absolutely symmetrically. On 
an inclined plane, however, the action of the wind on 
the front or advancing edge of the plane is different from 
that on the rear or trailing edge of the plane; hence, we 



_>88 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



can no longer say that the center of pressure is at the change the position of the center of gravity by placing 

a small lead weight on the front edge. Then if the cor- 
ners at A and B, Fig. 13, are turned slightly upwards 
while the whole is given a lateral dihedral angle as shown 



geometrical center of the plane. 

The result of the double action of the air-current with 
pressure below and suction above, both unequally dis- 
tributed, is that the total reaction on the plane is ap- 
plied at a point C (Fig. 11) nearer to the leading edge 
A than to the trailing edge B. This point C is called the 



fLeac/ Weight 



C 



Fio. 11 In a flat plane, center of pressure C moves toward 
the leading edge A as the angle of incidence becomes smaller 

center of pressure of the plane. In a flat plane, C moves 
toward the forward edge a<s the angle of incidence becomes 
smaller, until when the angle is zero it reaches the point A. 
The curve, Fig. 12, shows the position of the center of 
pressure on a flat plane for different angles of attack. 
It will be noticed that from 15 deg. to deg. the center 
of pressure moves very rapidly towards the front of the 
plane A. The wind is supposed to be blowing from the 
right in a direction perpendicular to AB. Aeroplanes al- 
most never fly with an angle of attack greater than 13 
deg. This change in position of the center of pressure 




Fio. 12 



BS/J 

30 

Location of center of pressure on flat surface for 
various angles of attack 



very easily can be proven by a well-known and very 
simple experiment. If we take a strip of light card- 
board about 8 in. long by 1 1/2 in- wide we know that the 
center of gravity will pass through the geometrical center. 
Now if we were to project this through the air in a hori- 
zontal position with the long side forward, the center of 
pressure being at the front end and acting upwards, 
while the weight at the center of gravity acts downwards, 
a couple would be produced causing the plane to rotate 
witli the advancing edge going up. This shows that the 
center of pressure is near the front edge. 

We cannot change the center of pressure but we can 



C 

FIG. 13 Center of pressure located close to forward edge of 
cardboard strip used in simple experiment 

in the lower part of Fig. 13, the plane on being projected 
in the air is seen to glide almost perfectly. A little prac- 
tice is necessary in adjusting 1 the weight. 

Figs. 14 and 15 show pressures and the path of the 




FIG. 14 Pressure diagram for upper and lower faces of curved 
surface with inclined chord. Compare with Fig. 10 




D'recf/on of 
Wind 



Fio. 15 Location of center of pressure on a curved surface at 
various angles of attack. Compare with Fig. 12 

center of pressure for a curved surface. It will be noted 
first how greatly the suction effect on the top of the plane 
has been increased, and that from zero to 15 deg. (see 
Fig. 15) the center of pressure moves in exactly the re- 
verse direction from the way it does in a flat plane. This 






TIIKOKY OF 1 I.KiHT 



latter cfl'cct has .-i i cry iiiiport:iiit bearing when wr conic 
to stability. 

Cambered Planes 

1'i^'. lii IN I roiiiili sketch i>t' wli.it our might call :i typ- 
ir:il win-; section. Noli- tin- difference in profile |.. 
tlir top anil liottoin surface,. Tlir i-lmril max In ilrliiiul 
as tlir straight lim- whirh is tangent to tlir unilrr surface 
of tlir arrnfuil si-rtinii, front ainl rrar. and the aiiifle of 
attai-k as tin angle hrtwrrn tin rrlatiir wind anil the 
rliord ot tin aerofoil. We may rile tin- following sim- 
)ilc expression for the lift and the drift: 

The Lift (10 = k t 8V 
The Drift (D) = L/r. 




I i... !' Sketch of 



typical wing section with aeronautical 
trrms iiuiii .iti-il 



'. film nt k, depends upon the shape of the aerofoil 

anil the angle of attack and must be determined experi- 
mentally. The <|iiantitv r, also determined experimen- 
tally, is railed the lift-drift ratio and measure-, the cffi- 
I'icncv of the aerofoil. 



CfiAHACTCf*l<3TtC ^SECT/ON 




AND L/ O VA.L UC^S 



-Ot 3t 



O< 3? 



0020 



03 , 



JH.Z 




O" / 



Yo/ 



Xw 



OS 



^6 



iV 



, 



7-a- & /cr/r/2'/3r/4'/s'/6'/7'/a'/9'2a' 



AN&LC OF /NC/OENCe Of WIM6 CHORD 
MO. 17 ( urv.s .showing values of k L and Lift/Drift ratio for 

a typical winp section 



l-'i>t. 17 -nr, two rur\t, fnr m m-rofnil of th, sn-tioii 
shoHii. Th. tir,t riirx. j.i\rs the values of Ilir i|ii.intit\ 
k, for different nnjjles of attack, while tin serond ciirxc 
In \.ilur, of tin- litt drift ratio. 

1 or i \ -niipli . sup|x>se that an aeroplane with aerofoils 
of the Upr shown, lifting surfaer i!ii si), ft., is Hying at 
an angle of attn. k of II drg., and with a \elo-ity of 7<> 
m. p. h. \\'lrit will l.c the lift and the drift ? 

I'roni the eh.-irt. Fig. 17. we nnd that for this t\p. of 
plan, and angle of attack k L (UMIiiH and r II, h. nee. 

L = k. SVJ = O.OOJ8 XOX (70)s = 8>J lb. 

I 
D = = =73 II*. 

r 11 

If now we elian^r the angle of attack to ;fl ., d< ^.. krep- 
illg tile surface and velocity the same, \vr tind from the 

ehart that k L = 0.0014 and T=- 18.5, h< D 




Horizontal Flight 

For horizontal flight the lift produced Ity the machine's 
velocity must nt all times exactly eijual its weight. 1 
if the lift were less than the weight, the pl.-mc would 
fall, while if the lift were greater than the weight, the 
machine would In-gin to climh. \\'e therefore can replace 
the lift l.y the weight \V. Then we would have for hori- 
zontal flight : 

Weight (\V) k. M 

and the drift (D) =\\ r 

For example, a given aeroplane weigh, (with load ) 
IK(K) ll>s. Its aerofoils arc of the type illustrated and 
the lifting surface i, 120 aq. ft. What will 1 it, v. 
locity for horizontal flight at an angle of attack of 12 
leg. ? 

From the ehart, Fig. 17. we find that for this type 
of plain- and angle of attaek. kL= <>.<>< i-J!), whence, ' 

I. = W = k L SV= or 1,800 = 0.00i9 X 1 X V 



trnns|x>sinp, V' = 



ura 



.0029 X 120 
hrncr, V= V*,17i = 7i m.p.h. 

If now we reduce the ani'le of attack to 5 deg., the 
ehart. Fig. 17. shows that k,_ bcronn s (i. (Mil 7.1. whence. 

1,800 = 0.00173 X liO X \ 
transposing, V = - 



O.(l017i X HO 



HCIKT, V = VH^'i or 93 + m.p.h. 

The above example ill-istrates this important principle 
that, since a machine in horizontal flight, except for a 
slight loss due to consumption of gasolene, main) '.in, a 
constant weight and a constant surface and since k j_ for 

a given plane depends solely upon the angle of attaek, the 



290 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



velocity for horizontal flight is completely determined 
when we know the angle of attack. Now since the pilot 
can control the angle of attack by means of his elevators 
he can control the velocity for horizontal flight. 

Fig. 18 shows four different positions of the plane cor- 
responding to four different angles of attack. In each 
case the machine is flying horizontally, though at first 
sight one might think that in position 4 the machine was 
climbing. 




FIG. 18 
FOUR POSITIONS FOR FLIGHT 

(1) Minimum angle. This is the smallest angle at which hori- 
zontal flight can be maintained for a given power, area of surface, 
and total weight. The minimum angle gives the maximum hori- 
zontal flight velocity at low altitude. Note that the propeller 
axis is inclined slightly downwards when flying at this angle., 

(-2) Optimum anyle. This is the angle at which the lift-drift 
ratio is highest. In modern airplanes the propeller axis is gen- 
erally horizontal at the optimum angle, as shown at (^) in the 
above figure. Note that in the position shown the velocity of 
the airplane will be less than when flying at the minimum angle. 
The effective area of wings and angle of incidence for the opti- 
mum angle are such as to secure a slight climbing tendency at 
low altitude. 

(3) Rest climbing angle. This angle is a compromise be- 
tween the optimum and maximum angles. Modern airplanes are 
designed with a compromise between climb and horizontal veloc- 
ity. At this angle the difference between the power developed 
and the power required is a maximum, hence the best climb is 
obtained at this angle. See Fig. 22. 

(4) Maximum angle. This is the greatest angle at which 
horizontal flight can be maintained for a given power, area of 
surface and total weight. If the angle is increased over this 
maximum, the lift diminishes and the machine falls. 

It would seem at first that we have entirely neglected 
the engine, especially as there is a general impression 
that the velocity of a machine depends upon the power 
of the engine, while as a matter of fact the form of wing 
sections together with the plane's dimensions are equally, 
if not more, important. In the preceding discussion we 
have simply assumed that the engine had the necessary 
power to maintain the plane at such a velocity as was 
determined by that angle of attack at which the pilot 
drives the machine. 

Engine Power 

The power of any engine is measured by the velocity 
at which it can move a body against a given resistance, 
and its unit, the horsepower, may be defined as the power 
required to lift one pound 33,000 ft. in one minute or 
375 miles in one hour, or the power required to lift 375 
pounds one mile in one hour. 

We must therefore multiply the total resistance offered 
to the aeroplane, which consists of the drift plus the para- 
site resistance multiplied by the velocity of the machine, 







































.U 

18 
/6 
14 

8 
6 
4 

a 












































































































































** 


. 






/ 






N, 


















S" 


--" 








f 


fcw^. 


V 


h 




\ 












^ 


^ 












1 






* 






s 


s^ 






X 






~/ 


^, 








1 
















^x 


^ 
































/ 




\ 






























/ 








\ 


























7 












\ 






















' 
















K, 
















/ 


/ 






















1 .. 










/ 




































/ 


































/ 

















































































































































.004 



003 



.002 



.001 



4 6 6 /0 12 /4 /6 /d 
Anq/e of/ncic/ence 

FIG. 19 Value of k L and Lift/Drift ratio for a given niachin 

and divide the result by 375 to get the horsepower re 
quired. Or, written as a formula: 

(Drift + Parasite Resistance) X Velocity 

= Horsepower 
375 

From the above expression for horsepower, it will b 
noted that since the drift for a given machine depend 
solely upon the angle of attack, and the parasite resist 
ance depends upon the square of the velocity, which i 
turn depends upon the angle of attack, we may state tha 
for a given machine with its load, the horsepower is com 
pletely determined when we know the angle of attack a 
which the machine flies. 

Fig. 19 corresponds for the entire machine to Fig. 1 
for the aerofoil itself and gives the value of k L for a give 

machine, as well as the lift-drift ratio. 

Fig. 20 gives in the heavy curve the power require 
to drive the machine at the angles of attack marked o: 



iUU 

30 
50 
70 

\ 60 

30 

20 
















































































































































I 


''I 


'/ 















V 


















^ 


-0 










_ 


r\ 


-1 


=>A 


f/ 


















^ 









Iff 


W 


'. 


t 




W_ 






It 








s 


^ 


W 


tf 


. 


fc 




o 










( 







*^ 


1 
















t 


r 












/ 


, 


^ 






I 


/i 


/)/ 


)/ 




J / 


| 


</ 












s 


s 


' 




. 


,- 





- 












/ 














* 




.' 


















9 n 


rix 




o 














\ 




c. 




/i 


^ 


V 


' 


^ 




/ 






















^ 












_ 


^ 


*^ 






















/^ 


- Jj ' 


^ 






4 


^ 


^ 


^t 






s. 


c-> 


rl 


fit) 


'->- 


/p 












/(. 





o 


t 


-) 












~r 








f.. 


f. 





1 


~y 


^- 


-^ 




















<-. 


-,* 


t/ 


fa 


^.. 


n- 












% 


















^ .. 








- 
































,i 






mm 


1 
































ffu 























































40 45 60 tf 60 65 7O 75 60 85 
>peed 'in rr>//e<s per hour 

Fio. 20 Showing power required at different angles, als 
power delivered 



TIIKOKY OF FLU. II I 



the riirvr. which correspond to tin- sp. ed in miles ]><-r 
hour gixcn at tin- bottom. The otlii-r set of curxes. four 
of tin-Ill dashed .'iliil one ;i li^ht line, unc (lie power dc 
livercd to the machine by the engine through the pro- 
pellcr. The latter would I e straight hori/.ontal lines were 
it not for the tact that the efficiency of the- propeller varies 
with the xdocity of the aeroplane. The orclinates as 
show n on the left side of the diagram correspond to 

horsepower. 

I. (I us .(insider the case where the cnuinc is making 
l.i ><> r.p.ni. It will lie seen that if the pilot changes his 
clcxators so as to My with an angle of attack of a little 
less than 1 detr., or of a velocity of about 82.5 m.p.h.. he 




30" 



Fio. .'I Showing rapid changes in wind velocity in short 
spaces of Him- 

will be using every particle of power that his engine can 
deliver at that speed. Any slight decrease in the angle 
of attack will cause him to go down probably in a nose 
dive. As he increases the angle of attack we come to a 
point where the distance between the two curves, power 
delivered and power required, is the greatest. Here we 
will have the greatest excess of power over that used for 
horizontal flight, all of which can be used in climbing, 
i ! that point will be the position for maximum rate 

of climb. It is indicated by the vertical dash line marked 
m,,.,imum rlimb at an angle of attack of a little less than 
6 deg. or a velocity of a little over 55 m.p.h. Increas- 
ing his angle of attack still further, or at about 8 deg., 
which is the lowest point on the curve, where the horse- 
power required for horizontal flight is only 30, we get 



a point of most i ..inoinic.il flight. Then, as we decrease 
the angle of attack, tin- power n quired rises rapidly until 
at Hi m.p.h. the two curves cross again and any iner. IM 
in the angle of attack would cause the machine to stall in 
I!K sense of going down, which might take the form of 
either a nosi- div . or tail slip. It is well to compare this 
with Fig. 18. 

It is also interesting to compare this with l-'ig. 21, 
taken from I.angley's Thr Stored Knrri/fi of the It'inil, 
and which illustrates the rapid changes in the velocity 
of the wind occurring in short intervals of time. The 
xertical lines represent spaces of one minute and the hori- 
zontal lines wind speeds differing by I m.p.h. It will 
be noticed that between 32 and 21 min. the wind fell 
from about 37 m.p.h. to 12 m.p.h. and rose again to :<H 
m.p.h. On account of the momentum of the aeroplane 
it would be practically impossible for its actual velocity 
to change with anything like that rapidity, and as the 
lift depends upon the square of the velocity it is cxidint 
that the pilot would experience a series of " humps " 
when the velocity increased, and momentary drops when 
the velocity decreased. The feeling has been likened to 
a motor boat driving rapidly through a choppy sea. 

Power to Climb 

Suppose the center of gravity of a machine be moving 
in the direction AB, Fig. 22, with a velocity of V miles 




l-'iii. -'-' -Calculation .of power required to climb 

per hour. The horsepower will then be the sum of two 
components, viz., that necessary to overcome the wind 
resistance, as already given for horizontal flight, and that 
necessary to lift the machine through the distance CH in 
the time required for the machine to travel from A to M. 
Now if AB be taken to represent the distance the mnchine 
travels in an hour, BC would then represent the velocity 
of climb. The power consumed in climbing is equal to 
the product of the weight of the machine in pounds by 
the velocity of climb in miles per hour divided by .<?.''. 
Let us call AB/BC the climbing ratio R which gives us 
BC = AB/R = V/R. We will have then the power ex- 
pended in the climb alone equal to WV/R, and the total 
horsepower becomes: 

(drift + parasite resistance) V \VV 
Horiepower = 



174 



375 It 



The case of special interest is where the horsepower 
becomes *ero. This is the condition when the engine is 
shut off on a glide. 
When, 

(drift + parasite resUtanee)V WV 

-(- - - = O, 

375 374 R 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



this reduces to 



W 



(drift + parasite resistance) 



\zoo 



\/0 



f7-~. 



75 



W 45 50 55 60 65 70 75 dO 85 
<Speec/ in roi/e-s per hour 

Fio. 23 Showing how drift, parasite resistance and gliding 
motion depend upon angle of attack 

It should be noted that the value of R is negative, due 
to the fact that the machine is gliding toward the earth. 
Now since both drift and parasite resistance depend upon 
the angle of attack, the gliding velocity and slope depend 
upon the angle of attack, and are under the control of 
the pilot. This is illustrated in Fig. 23. 

Stability 

One of the most important considerations in an aero- 
plane is stability, which is generally considered under 
three (leadings, viz., longitudinal, lateral and directional. 

Lonr/itudinal stability. This stability is needed to 
keep the aeroplane from pitching nose downward or tip- 
ping backward, nose up and tail down, whenever a gust 
or eddy is encountered. 

Flat surfaces 'are longitudinally stable because, as 
shown in Fig. 12, the center of pressure moves toward 
the leading edge as the angle of incidence is decreased. 
Fig. 25 shows four positions of a flat surface moving 
from right to left. Moving horizontally as in position A 
the center of pressure is at the leading edge, and when in 
the vertical position D the center of pressure coincides 
with the transverse center line of the surface. However, 
suppose the surface to be moving as at C and a sudden 
gust of wind tips it into position B with a lesser angle 
of incidence. Then the center of pressure moves for- 
ward, introducing a greater moment and tending to force 
the plane back into its original position C. On the other 
hand, if the surface assumes too great an angle, the cen- 
ter of pressure moves back and the rear is forced up, 
causing the surface again to resume its original position 
C. Thus, if it were not for the fact that the flat surface 
has a very poor ratio of lift to drift, it could be used in 
aeroplanes to advantage, due to this inherent longitudinal 
stability. 



Next consider Fig. 26, giving three positions of a cam- 
bered surface, which has a much greater lifting efficiency 
than a flat surface. It is also supposed to be moving 
from right to left. In position C the center of pressure 
coincides with the transverse center line. Supposing this 
surface to be moving in attitude B with the center of 
pressure at approximately the position indicated. If it 
is suddenly tipped into position A, it will be seen that 
the front part has a negative angle of incidence, which 
results in a downward pressure on this portion. The cen- 
ter of pressure of the surface being the resultant of all 
forces acting, it is obviously affected by this action at the 
front, and moves backwards. If the surface is tipped 
still further, the backward movement of the center of 
pressure is increased and therefore there is still less tend- 
ency to push the front up, when such a tendency would 
be most desirable. On the other hand if the angle of in- 
cidence becomes suddenly greater than the normal posi- 
tion B, the pressure on the front edge decreases and the 
resultant center of pressure moves forward, thus tend- 
ing to push the front up and give the surface a still greater 
angle of incidence. 

Therefore, it is necessary to have some way of com- 
pensating for this instability of cambered surfaces, and 



Fara/M to Chord 
of Lower W/ny 




STAGGER and DECA LA GE ~^ 



GAP' 




LA TERAL DIHEDRAL anJ 3 PAN 




LONG/TUDINAL D/HEDRAL 

FIG. 24 Illustrating meaning of some aeronautical terms 



TIIKOHV or 1 l.KiHT 



298 




- ' 



'Mir rrntrr nf pressure of u flat plnnr innvrs forward 
us the angle nf inciilencr i- il 




.. 



.'li Tin- center nf pressure nf 11 curxrd .siirincc mmrs 
forward with decreasing miglcs of incidence up to alxiut I.' di ;;. 
Hi luw this angle it re\erses and moves toward the center again. 




.'? Illustrating how the rear surface has its angle of 

ineidi-nee rriliiri'il in greater proportion than does the front 
siiri'.uv when the cnmliination is tip|M-d downward. 

this is dour hv tin- use of .-in auxiliary stal>ili/.ing surface 
some distance hack from the main surface and set at a 
lesser angle of incidence than the main surface. Such a 
stabilizer is a necessary feature of all modern aeroplanes. 
Fig. 27 shows two such surfaces in tandem, thus forming 
an elementary aeroplane. Consider the aeroplane to be 
traveling; horizontally with the angle of incidence of the 
main surfaces fi dcg. and the rear one-third of this, or 2 
(I. ^. Now supposing a sudden gust pitches the plane into 
some such position as shown in the lower part of the dia- 
:n. The .ingle of incidence of both surfaces is now 
reduced say 1 deg., the main surface being at a ' deg. 
angle and the rear surface at 1 deg. In other words, 
the main surface has lost only about 17 |HT cent, of its 
angle of incidence, whereas the stabilizer has lost M per 
cent. Consequently the stabilizer has lost more of its lift 
than the main surface, and it therefore must fall relative 
to the position of the main surface, bringing the combina- 
tion back into normal position again. On the other hand, 
if the front of the plane is suddenly forced up. the sta- 
bilizing surface receives a relatively greater increase in 
angle of incidence than the main surface, hence relatively 
greater increase in lift, pausing the back end of the plane 
to !>< brought up until the combination again is normal. 

I.alrral ttahility. This stability is necessary to pre- 
vi nt the machine from rolling about its horizontal axis. 
It is difficult to secure, but is often promoted by having 
a slight lateral dihedral angle between the upper wing 
urfaccs. as .shown in Fig. 28. Should the aeroplane sud- 




dcnly be tip|>cd to one side, in the position shown to the 
right of the diagram, the planes on the (low n side In . om< 
more nearly hori/ontal, whereas, those on the other side 
assume an angle s'lll greater than they had when Hying 
normally. Thus, the effective projected lifting snrl 
tin side A is increased and that on side M is deer 
bringing the plane back to its normal lateral position 
Other features arc introduced to aid lateral staliility, 
such as "wash in" on the left side to give this side slightly 
more lifting ability to compensate for the tori|iic of the 

propeller. 

Dirrclional *tal>ility. Such stability aids in keeping 
the plane on its course. In order to prevent yawing with 
every gust of wind, the vertical tail fins present on nearly 
all modern planes are used. Referring to Fig. .'! A. sup 
pose a sudden gust of wind to deflect the aeroplane from 
its normal course A so that the nose points off the course 
to the pilot's left, as indicated by the dotted lines in 
position B. This swings the tail around to the right so 
that the right side of the vertical fin presents a flat sur- 
face to the wind pressure resulting from the tendency of 
the machine still to move forward in the direction A, due 
to its inertia, even though it is temporarily pointing in 
direction H. A moment with arm r is thus set up. which 
tends to swing the plane back on its vertical axis until 
the fin is again parallel to the direction of the relative 
wind. The action is similar to that of a wind vane, tin- 
vertical fin of which always keeps it [minting in the di- 
rection of the wind. 




Fio. 29 Diagram to show action of vertical fin in preserving 
directional stahilitv 



CHAPTER X 



SHIPPING, UNLOADING AND ASSEMBLING 

Shipping instructions Marking boxes Methods of shippping Railroad cars used Unloading Method of load- 
ing on truck Tools required Unloading from truck Unloading uncrated machines Opening boxes As- 
sembling Fuselage and landing gear Center panel and wings. 



Shipping instructions. Boxes in which aeroplanes or 
parts thereof are shipped should be marked with the fol- 
lowing: 

Destination, or name and address of consignee in full. 

Sender's name. 

Weight of box (gross, net and tare). 

Cubic contents (or length, width and height). 

Box and shipment number. 

Hoisting center. 

" This side up." 

Methods of shipping machines. Machines are shipped 
either by loading in a railroad car without crating, or by 
crating in two boxes. In the latter case the wings, cen- 
ter section panel, tail surfaces, landing gear and propeller 
are removed from the fuselage, and the fuselage, landing 
gear, propeller and radiator are packed securely in the 
fuselage box. The other parts are packed in the panel 
box. All aerofoil sections are stood on their entering 
edges and securely padded to protect their coverings. 
Struts are stood on end. 

If the machine is not to be crated only the following 
parts are removed wings, center section panel, tail sur- 
faces and propeller. The fuselage is loaded into the rail- 
road car and allowed to rest on the landing gear. The 
latter should be blocked up, however, to take the load off 
the tires of the landing gear wheels and off the shock 
absorbers. The fuselage must of course be securely fast- 
ened in the car to prevent movement in any direction. 
The wings and other separate parts are crated against 
the sides of the car. The wings are secured with their 
entering wedges down and carefully padded to prevent 
damage. 

Railroad cars used for transportation.- If possible 
open end or automobile cars are used for transportation 
of aeroplanes. Sometimes with crated machines gondola 
cars are used, and with uncrated machines, ordinary box 
cars having no end doors. In the latter case, however, 
it is necessary that the side doors of the railroad car be 
as wide as possible, to allow working the fuselage in and 
out without damage. 

For transporting machines (either crated or uncrated) 
from the railroad, a flat top truck is used. If the truck 
is short it will be necessary to use a trailer to support the 
overhang of the boxes. 

Unloading 

Method of loading on truck. Before unloading a ma- 
chine, everything in the railroad car should be inspected 

294 



for loss or damage. If everything is O. K. proceed with 
the unloading, but if any loss or damage is discovered re- 
port fully at once to the receiving officer and await his 
instructions before doing anything further. 

The tools required for removal of aeroplane boxes from 
the railroad car are: 1 axe or hatchet, 2 crow bars, 6 or 8 
rollers and 100 ft. of 1 in. rope. 

The cleats holding the boxes to the car floor are first 
removed with the axe and crow bars, and the panel box 
removed from the car. If the fuselage box is not marked 
to show which is the front end it should be lifted slightly, 
if possible, first at one end and then at the other, to de- 
termine which is the engine end. This end, being the 
heavier, should come out first if possible. 

The truck is backed up to the door of the car, rollers 
are placed under the fuselage box and it is then rolled 
out onto the truck. The rope is now used to fasten the 
box to the truck. After this is done the truck is moved 
forward slowly and the box is thus pulled out of the 
car. If a trailer is to be used it should be placed under 
the box before the latter is taken all the way out of the 
car. 

When taking the fuselage out tail end first, the same 
methods are used, except that the light end is blocked up 
when removed from the car and a truck is put under the 
heavy end. 

When moving along roads care should be taken to go 
slowly over rough places, tracks and bad crossings. It is 
also a good policy to have a man on each side of the box 
to watch the lashings and see that nothing comes loose. 

Panel Box 

The wing box (or panel box) is removed from the car 
in the same manner as the fuselage box. 

Unloading boxes from truck. For this work 2 planks 
about 2 in. x 12 in. x 12 ft. long should be used. These 
should be fastened to the end of the truck with one end 
resting on the ground, so that they will act as skids. The 
tail end of the fuselage box is depressed until it rests on 
the ground, then by moving the truck forward carefully 
the box will slide down the planks onto the ground. 

Unloading uncrated machines. In this case all of the 
smaller parts should be removed first. Then the cleats 
and ropes are removed which hold the machine in the car. 
Two long planks are placed from the door of the car down 
to the ground and are used to roll the machine out of the 
car. 

Opening boxes. A screw driver and bit brace should 



NU r\I.()Al)IN(. \\D ASSEMBLING 



!>< used to ri-moxc tin sen -ws in the tn|i. sides .uid i -nils 
of the lxi\. Tin- top i- removed tirst. then one side. AH 
smaller parts nt tin iii.-ifliinr should In- t;ikrn out. after 
which tin- remaining side of tin- lm\ is removed, and lastly 
tin i mis. 

/> ^inl'liiii/ ii in in- lii in-. Tin- landing gear shoidil In- 
put on first. To do this tin- fuselage must In- raised hv 
our of to ini-tliods. Tin- first is by cliain falls or Murk 
and tackle. Tin ro|n- slinu should In passnl iindrr the 
engine sill just to (In- rear of the nose plate. Tin- tail 
of tin- inai-liiin- is allowed to rest on tin- tail skid while 
the nose is raised. The second method is by shims and 
blocking. This latter method is the most common hei-.-iuse 
chain falls are not always a\ ail-iMc. l-'.nutigli Mocks 
.should In- secured to raise the fuselage high enough to slip 
the 1 -iiiilin^ year underneath. The tail is tirst raised by 
J men and Mocks are placed under Station 5 or the rear 
wini; section strut. The blocking must be directly below 
the strut and must have padding upon it. Then the tail 
is depressed and another block is put under the forward 
wing strut. This operation is then repeated until the 
fuselajjc is hitrh enough for the landing gear when the ma- 
i-liine is blocked under nose and tail and the other blocks 



tour men arc all that xhould br 

n-(|uircd for this second method. 

Assembling Wing* 

r the landing grar is nssemMi d the center s. 
pin. I should be attached and approximately lined up. 
Then tin wind's .., rt - assembled. There are two methods 
for il.,in- this; one i* to put on the top plains, place sup 
purls under the outer edges, then put in struts and luwei 
planes and connect up the wires. The other method is 
to assemble the wings completely while on the ground. 
\\ Mitts are stoxl on their entering nine, struts are put in 
and wires tightened up to hold the wing irrtioiis together. 
Then tin- wings are attached to fuselage by turning them 
over and attaching the top wing tirst. then the lower wing. 
One side of the machine must IK- sup|xirted until the oppo- 
site set of wings is attached. After wings arc all at- 
tached, then the tail surfaces should be assembled to the 
body. The horizontal stabilizer should go on first, then 
the vertical fin. rudder and elevators in the order named. 
On some machines the elevators will have to be put on 
before the rudder. After everything i* assembled the 
machine is put in alignment. 



CHAPTER XI 



RIGGING 

Fuselage Construction Longerons Struts Fuselage covering Monococoque Landing gear Struts - 
Bridge Axle box or saddle Axle and casing Wheels Tail skid Shock absorber Wing skids Pon- 
toons on seaplanes Flying boat hull Wing construction Front and rear spars Ribs Cap strip Nose 
strip Stringers Sidewalk Struts Wire Bracing Wing covering Dope Inspection windows - 
wires and terminal splices Aircraft wire Strand Aircraft cord or cable Terminals and splices Solder 
ing Turnbuckles Locking devices. 



Rigging deals with the erection, alignment, adjustment, 
repair and care of aeroplanes. 

Aeroplanes are of light skeleton construction with parts 
largely held together witli adjustable tie wires, hence they 
easily can be distorted or their adjustment ruined by care- 
less or improper rigging. The efficiency, controllability, 
general airworthiness and safety of machine and pilot 
therefore depend very largely upon the skill and con- 
scientiousness of the rigger. 

For purposes of description the aeroplane may be di- 
vided roughly into three parts (exclusive of the power 
plant). These are the body or fuselage, the wings or 
aerofoils and the landing gear. 

The fuselage is the main structural unit of the aero- 
plane. It provides a support and housing for the power 
plant, contains the cockpit for the pilot, and the instru- 
ments and control mechanism. The rear end of the fuse- 
lage carries the rudder, elevators, stabilizing fins and the 
tail skid. The wings or aerofoils are attached to the 
fuselage through suitable hinged connections or brackets 
and the fuselage is supported by the wings when the ma- 
chine is in the air. Conversely the wings are supported 
from the fuselage when the aeroplane is on the ground, 
as in that case the whole weight of the machine is sup- 
ported by the landing gear and the tail skid, both of which 
are attached under the fuselage. 

The body or fuselage is of trussed construction, a form 
which gives great strength and rigidity for a given weight 
of material. Parts assembled together in the form of a 
truss are spoken of as members. Those which take a 
thrust only are called compression members, while those 
resisting a pull are known as tension members. 

Other members may be either tension or compression 
members, depending on how the load or force is applied 
to them at any given time. There are also members 
subject to a shearing stress and others to cross-bending 
or compound stresses. 

The fuselage is usually constructed witli four main lon- 
gitudinal members running the full length. These are 
called longerons. They are separated at intervals by 
compression members termed struts. The whole struc- 
ture is in turn tied together and braced by means of 
diagonal wires, fitted with turnbuckles for adjustment, 
which go under the general name of wire bracing or 
stay wires. 

Stay wires in certain parts of an aeroplane are desig- 



296 



nated as flying, ground, drift, anti-drift, etc. These will 
be considered later. 

That part of the surface of the fuselage which is 
bounded by two struts and two of the longerons is known 
as a panel. The points at which the struts join the 
longerons are called panel points or stations. The cu- 
bical space enclosed by eight struts and the four longerons 
is called a bay. Some makers, Curtiss for instance, num- 
ber the stations in the fuselage from front to rear call- 
ing the extreme front station No. 1. Others, such as 
the Standard, number these stations from the rear toward 
the front, calling the tail post zero. 

The longerons are made of well-seasoned, straight- 
grained ash*. They are curved inward toward the front 
end and usually terminate in a stamped steel nose plate. 
This is true particularly of aeroplanes equipped with en- 
gines of the revolving cylinder type. The nose plate is 
stamped from plate steel about .10 in. in thickness. This 
plate not only ties the longerons together at the front end 
of the fuselage, but supports one end of the sills on which 
the engine rests. In some types of planes it also forms 
a bracket for supporting the radiator. In other types 
of aeroplanes the longerons may terminate at the front 
end of the fuselage in an open frame which forms the 
support for the radiator and also supports the front ends 
of the engine bearers or sills. The two upper and the 
two lower longerons are brought together in pairs one 
above the other at the rear end of the fuselage, and are 
joined to the tail post or vertical hinge post on which 
the rudder is mounted. 

Lightened Construction 

In order to lighten the construction of the fuselage as 
much as possible, the rear portions of the longerons are 
often cut out to an I section and spruce is often substi- 
tuted for ash for the rear half, suitable splices strength- 
ened with fish plates being used wherever joints are made 
in the longerons. It is possible to lighten the rear por- 
tion of the fuselage in this way for the reason that this 
part of the body does not support as much weight or 
undergo as severe stresses as the forward portion. 

In a machine of neutral tail lift (one in which the rear 
horizontal stabilizers are set at such an angle that they 
barely sustain the weight of the rear portion of the ma- 
chine when flying horizontally in the air) the stresses in 
the longerons are exactly the opposite when the machin 






RIGGING 



-".'7 




Mum inj; priiicipul piirt.s of fuwlgr 



is in tli. air In those obtaining on the ground. \Vln-n thr 
urn-bine i, .it rest mi the ground it is supported near the 
front ami n ar .mis of the fuselage liy the landing gear 
anil the tail skid. This method of support proiluees ten- 
sion in the lower longerons and compression in the upper. 
When in tin- air the niai-hine is supported by the wings 
which arc attached to the fuselage at the center whin 
ion. The system of supports, trusses and stay wires 
lictwccn the upper and lower wings transfers most of the 
.support from the wings to the center panel seetion of 
the upper wing. This results in tension in the upper 
lonyi runs and compression in the lower. 

The fuselage struts are usually made of spruce, al- 
though ash is sometimes used. The struts are joined to 
the longerons by means of metal elips. The eonstruetion 
of the clips, which arc usually Lent in I" shape, is such 
that each forms a partial socket for receiving the end of 
a strut or struts. In general, struts are subjected to 
compression only. For this reason spruce is the favorite 
wood for struts as it is very strong along the grain in 
tension or compression. The strength of steel, weight 
for weight, would have to be 18O.OOO Ibs. per square inch 
to eijual spruce for this purpose. Spruce is not. however, 
very strong across the grain and splits readily, henee it 
is not a great favorite for parts subject to shearing or 
cross-bending stresses. On account of the liability of 
spruce to splitting, the ends of the struts are sometimes 
encased iii copper ferrules or bands. This prevents crush- 
ing, splitting and chafing. 

Compression Struts 

When a member is subjected to a compression force it 
tends to bend or buckle in the center. To resist this tend- 
ency, struts subject to compression stress arc made larger 
in the center than at the ends. 

Ash i> selected for the longerons because it is strong 
for its weight (about 38 Ibs. per cu. ft.), very elastic and 
can be obtained in long, straight-grained pieces free from 
defects. It is strong across the grain so that it is able 
to resist the compression due to clips and struts attached 
at \arious points on the longerons. 

The metal dips in which the ends of the struts are 



mounted are punched from sheet steel, then pressed to 
form. They are frequently made of two or three sep 
aratc pieces which are then electrically spot-welded to 
gether. They are made of .*8 to .:! per cent, carlton 
steel. 

The lower cross mcml>crs of the fuselage at stations .( 
and \. numbered from the front, terminate in a half hinge 
to which the lower wing sections arc attached on either 
side of the fuselage. These cross-members ser\e as com- 
pression members when a machine is on the ground, but 
when it is in the air they become tension member*. 

Engine Bearers 

The engine bearers arc made of spruce with a strip of 
ash glued on top and bottom. They are further protected 
against crushing, at points where the engine supporting 
arms rest on the sills or stringers, by means of a copper 
hand. 

There is usually a fire screen between the engine space 
and the cockpit. This is to prevent injury to the pilot 
so far as possible in case of a back fire or fire in tin- 
engine space. 

The seat rails are short longitudinal members forming 
supports for the pilot's and observer's seats. These rails, 
which arc mounted on either side of the fuselage, are at 
taehed to adjacent vertical struts at the proper distance 
aloic the lower longerons. 

The rudder bar is a cross bar pivoted at its center and 
mounted a short distance above the floor of the fuselage. 
It is used to control the vertical rudder and is operated 
by the pilot's feet. Ordinarily the ends of the rudder 
bar project through the sides of the fuselage, working in 
suitable slots cut for them, and the rudder wires are at- 
tached to the ends of the rudder bar outside of the fuse- 
lage. In machines fitted with dual controls there arc. 
of course, two rudder bars and these are fastened together 
by means of wires connecting their outer ends. The rear 
of the two rudder bars is then connected to the vertical 
rudder in the usual way. 

Wing section struts are vertical or diagonal struts 
mounted above the fuselage and attached by means of 
strut sockets to the upper longerons. The wing section 



298 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



struts are used to support the center wing panel when 
the machine is on the ground and when in the air they 
help to support the fuselage from the center panel, the 
latter being supported partly by the upper wing sections 
which are attached on either side of it and partly by the 
lower wing sections which are braced to the upper sections 
and also attached on either side of the fuselage as pre- 
viously described. 

The strut sockets in which the lower ends of the wing 
section struts are mounted consist of U-shaped steel plates 
firmly attached to the upper longeron. The wing section 
struts are mounted between the side walls of the socket, 
usually by means of a heavy through-bolt. 

Standard Fuselage Construction 

The type of fuselage just described, which is of wood 
and metal construction, may be said to represent standard 
practice in this country at the present time. There are, 
however, other types of construction, such as the all-steel 
fuselage. In this the shape of the members and the meth- 
ods of joining them follow closely standard methods in 
structural steel work. It is claimed for the all-steel con- 
struction that it is lighter for a given size machine than 
the wood and metal or composite construction. 

The fuselage is usually covered either with canvas or 
linen material similar to that used for wing coverings or 
else with very thin panels of veneered wood. In the 
former case the longerons, struts and braces must carry 
all the weight and take up all the stresses to which the 
fuselage is subjected, but when a veneered wood covering 
is used, it contributes materially to the strength of the 
fuselage, consequently the framework of the latter may 
be made lighter. 

There are also fuselages of the monocoque type in 
which the strength is obtained not by a truss construction, 
but by the form and nature of the outer shell itself, this 
being made up of alternate layers of thin wood veneering 
and cloth until the desired thickness and strength are ob- 
tained. The various layers of wood veneering are laid 
with the grain running in different directions in the differ- 
ent layers. This type of shell or body, which is usually 
somewhat fish-shaped, possesses the necessary strength 
and elasticity without the system of struts and tie wires 
common to the ordinary or trussed type of fuselage. The 
monocoque construction possesses one marked disadvan- 
tage, however, and that is that it is very hard to repair 
in case of slight damage. 

It may be added that the monocoque or laminated wood 
construction is far more common in foreign countries, par- 
ticularly France and Germany, than in the United States. 

Landing Gear 

The landing gear is an assembly of struts, fittings, axle, 
wheels, shock absorbers and bracing wires whose function 
is to enable the machine to rise from and land on the 
ground and to furnish the main support of the machine 
when resting on the ground. 

The struts of the landing gear are of streamline shape 
to reduce the resistance when flying. They are usually 
made of well-seasoned, straight-grained ash or spruce. 
Very often they are further strengthened by several wrap- 
pings of linen twine. The struts with their fittings con- 



stitute important members and should be carefully exam- 
ined at frequent intervals. Failure or collapse of these 
struts would be almost certain to cause a serious accident 
when landing. 

These struts are attached to the lower side of the fuse- 
lage, usually to the lower longerons themselves by means 
of metal socket fittings. The lower ends of the struts 
on each side of the landing gear are joined together by a 
metal bridge. This bridge not only serves to tie the 
lower ends of the struts together, but it also forms a yoke 
or housing in which the axle box plays up and down. 
The bridge is made of a steel stamping or drop forging. 

The axle box may be in the form of a whole box or a 
half box. When it is in the form of a half box it is gen- 
erally called a saddle. Its purpose is to support the 
axle and to guide its vertical motion in the bridge. The 
saddle may be either of bronze or aluminum. It is held 
in its place in the bridge by a wrapping of elastic cord, 
which consists of a number of strands or bands of rubber 
bunched together and enclosed in a loosely-braided cover- 
ing. 

The assembly of the saddle, bridge and elastic cords 
: s called the shock absorber. 

The axle is made of steel tubing and is enclosed, be- 
tween the bridges connecting the pairs of struts, in an 
axle casing. This is made of wood, or sheet metal, built 
around the axle itself and is of streamline shape or sec- 
tion to reduce air resistance. 

The wheels are the ordinary type of wire wheels of 
rather small diameter and usually fitted with pneumatic 
tires. They do not, however, ordinarily run on ball bear- 
ings, as a slight amount of friction in the wheel bearings 
is of little or no consequence when leaving the ground 
at the commencement of a flight, and it assists somewhat 
in bringing the machine to a stop without going too far 
after alighting. The sides of the wheels are covered with 
linen cloth discs to decrease air resistance. 

Not all landing gears are like the one described, but 
this may be taken as standard practice. Some are pro- 
vided with a skid or a single wheel projecting ahead of 
and above the main wheels for the purpose of preventing 
the machine from taking a header or nosing into the 
ground on landing, in case it strikes the ground at too 
sharp an angle. Other minor details of construction will 
be noted, too, on different types of machines, particularly 
in the construction of the shock absorbers. 

The tail skid is a skid or arm projecting below the fuse- 
lage near its rear end. The purpose of the tail skid is 
twofold; first, to support the rear end of the aeroplane 
when on the ground or in landing, and prevent damage to 
the rudder and elevators and their controls, and secondly, 
to act as a drag or brake to assist in bringing the machine 
to a stop when landing. The tail skid is frequently hinged 
or pivoted where it is attached to the lower longerons and 
its upper end, extending above the pivotal point, fitted 
with rubber cords similar to those used in the shock ab- 
sorbers on the axle of the landing gear. This construc- 
tion acts the same way as the shock absorber and prevents 
damage to the empannage and rear portion of the fuselage 
when landing. 

Aeroplanes are often fitted with wing skids which con- 
sist of small auxiliarv skids under the outer ends of each 



RIGGING 



MO 



/Vase 




DrtniU of wing construction 



lower wing. These skids ordinarily do not come into 
;u-tion -ind an- only pro\ ided to prevent damage to the 
outer win^s in alighting on rough ground or in case a 
sudden side gust of wind should tend to upset the machine 
when alighting or rising. 

Landing Gear of Seaplanes 

: 'lanes and flying boats are of course fitted with 
entirely different types of landing gear from that de- 
scribed. Seaplanes are fitted with pontoons or floats suit- 
able for arising from and alighting on the water. I'sually 
there are one or two main pontoons under the forward 
section of the fuselage, these corresponding roughly to 
I lie main landing gear of the aeroplane. There is also 
a smaller pontoon mounted under the rear end of the fuse- 

H| one under the outer end of each wing to prc\ent 
the wings dipping or the whole machine upsetting in rough 
water. The flying boat is so constructed that the whole 
fuselage i> in the shape of a boat and the whole machine 
is therefore supported on the fuselage when resting on 

tier and when alighting and rising from the water. 
The Hying boat is also usually fitted with small auxiliary 
pontoons under the outer edge of the wings to keep the 
machine steady in rough water. 

Standard Wing Construction 

The main members running the full length of the wing 
are called the spars. They are usually spoken of as front 
and rear spars. Sometimes the front spar is called the 
main spar. 

The cross members joining the spars together are 

called rilis. There are two kinds of these, compression 

ril's and the web ribs. The function of the web ribs is 

men h in support the linen covering of the wings and 

ist the lifting force of the air, due to the forward 

motion of the aeroplane. There is not much end pres- 

igainst these ril>s. therefore, the central portion is 

cut out for the sake of lightening them. The function of 

inprcssion rihs is not only to resist the lifting force 



of the air, but also to take the thrust due to the star 

w ires. 

The ribs are not continuous, that is, they do not pass 
through the spars. The ribs are made in three sections, 
the nose section, center section and tail section. The nose 
section of a rih is the section which projects forward of 
the front or main spar. The renter section is the section 
between the front and rear spars. The tail .section of the 
rih is that which projects to the rear of the rear spar. 
Tin' nose sections and tail sections are sometimes called 
nose rihs and tail rihs and are also frequently .s|mkcn of 
as nose webs and tail webs, because they are cut out to 
web form. These rib sections are not, of course, called 
upon to stand compression stresses, as these stresses are 
all centered in or taken through the front and rear spa- 

A thin strip of wood running from the nose weh across 
the spars to the rear end of the tail webs (lengthwise of 
the aeroplane itself) and serving to bind all the wing 
parts or rihs together, is called the cap strip. There is 
top cap strip and a bottom cap strip on each set of rib*. 

Entering and Trailing Edges 

The front edge of the wing section which is the part 
carrying the nose webs or nose ribs is called the entering 
edge of the wing. The rear edge of the wing is known 
as the trailing edge. 

The nose webs are tied together by a strip of spruce 
running full length of the wing or crosswise of the aero- 
plane itself. This strip forms the leading edge of the 
wing and is called the nose strip. From the nose strip 
to the front or main spar, on the upper side of the wing, 
there is a covering of thin laminated wood called the nose 
covering. Its purpose is to reinforce the covering fabric 
as it is at this point that the effect of wind pressure due 
to velocity is most severe. 

Secondary nose ribs are placed between each pair of 
full rihs to give additional support to the nose covering. 

There are usually two rod-like members running from 
end to end of the wing through the central part of the 



;joo 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



ribs. These are called stringers and are used for the 
purpose of giving lateral stiffness to the ribs. 

The trailing edge of the wing is made of thin flattened 
steel tubing attached to the tail webs by metal clips. 

The spars are continuous throughout their length. Fur- 
thermore, they have reinforcements of wood at the points 
where the interplane struts connecting the upper and lower 
wings are attached. Steel bearing plates are bolted to 
the wing spars at these points. The bolts attaching 
these bearing plates to the wing spars do not pass through 
the spars themselves, but through the reinforcements. 
This is to avoid weakening the spars. 

Nearly all wood used in wing construction is spruce, 
with the exception of the nose covering which is made of 
bircli or gum wood, the web ribs, which are made of lam- 
inated wood, and small quantities of pine or other woods 
in the sidewalk and other unimportant places. 

The sidewalk is a boxed-in or wood-covered portion 
of the inner end of the lower wing. It furnishes a solid 
footing for the pilot or observer when entering or leaving 
the cockpit and for mechanics working around the engine, 
guns, instruments, control mechanism, etc. 

Steel hinge pieces are bolted to the inner ends of the 
wing spars and serve as a means of connecting the lower 
wings to the fuselage and the upper wings to the center 
wing panel. 

Interplane struts are vertical or inclined wooden struts 
of streamline section used to transfer compression stresses 
from the lower wings to the upper wings when the ma- 
chine is in flight. These struts are used in conjunction 
with diagonal stay wires which serve to transfer the load 
towards the center of the machine when in flight. 

The stay wires are divided into two general groups, 
those which take the drift load or fore-and-aft stresses 
due to the forward motion of the aeroplane, and those 
which take the lift load or vertical load due to the weight 
of the machine itself and the vertical resistance when in 
the air. The lift wires are again divided into those 
which take the load when the machine is flying and those 
which take it when on the ground. The wires which take 
the lift load when the machine is in the air are called the 
flying wires, and those which take the load when on the 
ground are called ground or landing wires. 

Drift and Anti-Drift Wires 

The set of wires in the wings which carry the drift 
load when flying are called the flying drift wires, or drift 
wires for short. There is no reversal of load in these 
wires when the machine is on the ground, but opposition 
wires are necessary to maintain structural symmetry. 
These latter are called the anti-drift wires. 

When the wings are covered it is of course impossible 
to inspect the internal stay wires of the wings, hence 
every precaution must be taken to guard against corro- 
sion. The wire used at this point is tin coated before 
assembling, the steel parts of the turnbuckles and other 
fittings are copper plated and when completely assembled, 
all the metal parts are given a coat of enamel paint. All 
screws, tacks and brads are of brass or copper. 

Wings are covered with a closely woven fabric. At 
present unbleached linen seems to give the best satisfac- 
tion. Owing to its scarcity, however, a satisfactorv sub- 



stitute is being sought for. A cloth made of long fibre 
sea island cotton is used to some extent and makes a 
fairly satisfactory substitute. 

Linen fabric weighs 3 1 /-; to -1% oz. per sq. yd. and has 
a strength of 60 to 100 Ibs. per in. of width. Its strength 
is increased 25 to 30 per cent, by doping, however. The 
weight of cotton fabric is 2 to 1 oz. per sq. yd., its strength 
30 to 60 Ibs. per in. of width, and its strength is increased 
20 to 25 per cent, by the application of dope. 

The cloth surfaces or wing coverings must be taut, 
otherwise on passing through the air they would vibrate 
or whip. This would not only increase the resistance to a 
great extent, but soon would lead to the destruction of 
the fabric. A preparation called dope is used to tighten 
up the fabric and give a smooth, taut surface. It also 
tends to make the cloth weather-proof. 

Dope should be easy of application, durable, fire re- 
sisting and have a preserving effect on the cloth. Dopes 
at present are divided into two classes or chemical groups, 
those which are made from a base of cellulose nitrate or 
pyroxylin and those made from a cellulose acetate base. 
The base is dissolved in a suitable solvent, such as acetone 
for instance, and sometimes other substances are added to 
preserve flexibility or prevent drying out and cracking 
and checking or to modify shrinkage. 

The greatest difference between these two dopes is in 
their relative inflammability. The acetate dope makes 
the fabric not fireproof, but slow burning. A cloth 
treated with this dope will shrivel and char before burn- 
ing, but one treated with nitrate dope will burst into flame 
immediately on the application of a lighted match or 
when exposed to a strong spark or puncturrd by a flaming 
bullet, etc. 

Inspection windows are often inserted in wing sections 
over and under certain control joints where the latter are 
carried inside the .wing section itself. For instance, the 
aileron control cables are frequently run inside the lower 
wing sections to a pulley attached to the front or main 
spar opposite the middle of the aileron, the cable then 
passing down at a slight angle and through a thimble 
or sleeve in the lower covering of the wing section to the 
point where the cable is attached to the aileron control 
marst. With this construction inspection windows would 
be set in the upper and lower coverings of the lower wing 
immediately above and below the pulley over which the 
control cable passes. The inspection windows are usually 
of celluloid or other transparent material firmly sewn 
into the wing covering material. 

Stay Wires and Splices 

Stay wires and cables are used extensively in aeroplane 
construction. Much of the safety of the machine and 
pilot depends upon the quality of the material in the stay 
wires, the care used in adjusting them and on the char- 
acter of the terminal splices. 

Three kinds of materials are used for stay wires : solid 
or aircraft wire, stranded wire or aircraft strand, and a 
number of strands twisted together to form a cable and 
known as aircraft cord. Aircraft wire is a hard drawn 
carbon steel wire coated with tin to protect it against cor- 
rosion. Its strength runs from 200,000 to 300,000 Ibs. 
per sq. in., depending upon how small it is drawn. Draw- 



RIGGING 



.(in 



<=a j 




^fcc 



>tc|.s in making an en.l splice in s,,|j ( | i rr 

ing increase! iolh the strength and hardness of this type 
of wire, but if drawn until too hard it cannot be bc,,t with 
safety. The aim is to pr.iducc .-, wire ,,f maxim,,,,, 
stren-tl,. ,,, ,(!, sufficient toughness to allow it to h.nd 
without fracture. A standard test for Unding is to 
grip the wir, ,,, ., \ ice whose jaws ha\e been round, d off 
16 in. radius. ,nd bend the wire back and forth 
fcroagfa an angle of ivd, - Had, bend of MI d,-g. counts 
as one Lend. The minimum number of bends f l)r various 
si/, s of aircraft wires should be as follows: 

ir. of II. ;v s (Mllir e \- . 6 _ 5 ,.,, with , iu , fra ,., |lr ,. 

PM wir. ... II. A; S. gaugr No. 8- brmls without fracture. 

B * B Wo. lo || | H . n ,|s without fracture. 

r wire of II. \ S u.,,,^. \,, i., ,; |M . |1(U tt j,, H , u , f rn( . tlln . 

wire of l\. & S. gaugr No. It _:, Len.K without fractiirr 

For wire ,,f . & S. gauge No. Hi :i | M -i,,| s without fnictiire. 

Air, raft strand is composed of n number of small wires, 
usually Hi. twisted together. The individual wir- 
tlie strand are galvanized or zinc coated before being 
twisted into the strand. The complete strand is more 
flexible than a solid wire of the same diameter and is 
therefore mor, suitable for stay wires that are subject 
to \ ibration. 

The stay wins of the fuselage at the engine and wing 
panels .re of aircraft strand or cord, but for the remain- 
ing stay wiros of the fuselage aircraft wire is ordinarily 

Is, .| 

Aircraft cord is much more flexible than Hie strand. 

d tor control cables where these must pass over 

aratively small pulleys. The usual constrm-tion of 

iff cord is 7 strands of ]<l wires each twisted together 

to form a cable. This specification is known as ~ \ 19 

i ord. The individual wires of the cord are very 

imall and are tin-plated before being stranded. 

For ., given diameter, the solid wire is stronger than 
ithcr th, strand or cord. Weight for weight, however, 
he cord is a little stronger than the wire, as shown by 
lowing table. 






Wright 

p*r 100 ft 

8At ll.s. 

6.47 Ibs. 



St n-ngth for a 

pivcu iliiiiui-ter 
5,300 Ilis. 
VOO Ibs. 



Strength fora 
given Wright 



A wire or cord is no stronger than its terminal splice. 

I he splice in iy be formed in a variety of ways. For 

"lid wir. the formation of the eye is important. An 

ye in which the reverse curve has the same radius as 

proper is called a perfect eye and is the one recom- 



mend, d Th. ms.d. ,| M1 u,.,r . ih, ,,, should l.e alH.,,1 
tunes the di under of tl.,- win ,|s, || 

aed capped wir 

rrule. somewhat lik. , .o,l,,l s|irill)f ,),,, , , , m 

'". ,s sl.p,,,.,! ,,,, r ,,. w,n and .1,, fri , ,,, 

I'll, r is then U-nt hack OTer th, ferrule Such 

'n.iMml will | ln( , ., ,,,i.. j( . r , r |1M( (>f 

tl'e stn.^th of th. nir,- ..self. \\ |,, n this t,,,,- ,,f ,,. rill 
f'ls ! is usually l,y sl.pping. If the fre,- end ,,l tl,. 
""I -l-wn. ,,f,, r | M . illK , H . n , ,,, I( . k (|V| . r , |l( . fi . rnilr 
Hi an additional wrapping of wire. Ih, elli.-.encv of the 
ernun.d as whole will I,, m.r.as,,) to HO per 'cent of 
t > strength of the wire. If ,| lr w | 1() |,. ,,. rmillll | js SI1 , 
end the efldency Mill U- mere. ,,,,) I,, IM.I p, T ,.,.,,, 

rill "K I" >ttic tests. This is misleading, how 

i" such tests take no account of live load sir, or nl.ra 

tlnll 

Another form of terminal is- made by substituting a thin 
metal ferrule or section of flattened tulx- for the wrapped 
"in ferrule. It can be made secure either by soldering 
twisting after U-ing put in place. This terminal for 
I've or vibrational loads is ,u|>crior to the wrapped win- 
terminal as then is not so much difference j n mass l 
the wire and the ferrule. 

Aircraft Strand Terminals 

The terminal eye of the aircraft strand is formed around 
a thimble. The free end of the strand is brought around 
the thimble and either wr;ip|d to the main strand with 
small wires and soldi-red, or the free end is spliced into 
the main strand. Hefore bending around the thimble, 
the strand is wrapped with fine wire in order to prevent 
flattening or caging of the rfrand. 

The terminal eye of the aircraft cord is always made bv 
splicing the free end of the cord into the main strands 
after wrapping the cord around a thimble. Sometimes 
the splice is soldi-red but more often it is wrapped with 
harness twine. Foreign engineers are opposed to solder 
ing. claiming that the disadi. -ullages in the wav of cor 
rosion and overheating of the wire outweigh the advan- 
tages of the stronger terminals. 

The theory of the splice is simple. A strand or wire of 
the free end is wrapped around a strand or wire of the 
main cord, care being taken to have the iay of the wires 
the same. Three to five complete turns are given, three 
for the first and four to five for the last weaves of the 
splice in order to taper the splice gradually. 

Objections to tnliirrinfl. The most serious objections 
to soldering are: a. overheating; b. corrosive action of 
fluxes It is very easy to overheat and soften the wire 
and this is all the more serious because the softening tak 
place at a point where the wire is enlarged by the joint. 
The str.ss is naturally localised at this point. 

Some of the so-called non-corrosiir fluxes will upon 
application In- found to IM- more or less corrosi\c. F.\.n 
with strictly non corroxi\ e fluxes, tiiere is a carbonaceous 
residue, due to heat. dri\,n into the interstices between 
tin- wires of strands or cordV This serves as a holder 
for moisture and will in time cause corrosion. 

The corrosive effects of acid fluxes can be neutralized 
by the application of an alkaline solution, such as soda 
water. Washing the soldered splice of a solid wire witli 



302 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



such a solution is very effective, but with strands and 
cords, where the acid is driven into the interior through 
the application of heat, it is questionable whether any 
system of washing will eliminate or neutralize the acid. 
Corrosion of the interior wires of a strand or cord may 
be concealed by a perfectly good exterior, giving an en- 
tirely false appearance of security. 

Turnbuckles 

Turnbuckles are made of three parts, the ferrule or 
sleeve, and the two ends. To distinguish the ends, they 
are called the yoke and eye ends, or the male and fe- 
male. 

Great care should be exercised when tightening or loos- 
ening turnbuckles that the cables are not untwisted or 
frayed. If the cables are untwisted a caging of the 
strands results which greatly weakens the cable. Cable 
that has been caged should be replaced. No pliers should 
be used when tightening or loosening turnbuckles. The 
correct method is to use two drift pins or nails, one 
through the terminal eye of the cable to prevent the end 
of the cable twisting, the other through the hole in the 
barrel of the turnbuckle. Pliers will scar the wires, which 
is objectionable for three reasons, the first two of which 
mav lead to serious consequences. These reasons are: 
First, breaking the protective coating given to guard 
against corrosion. Second, a nick or scar in a wire or 
cable which would weaken it considerably. The wire or 
cable may not show much reduction of strength under a 
static load or test, but with a live or vibrational load the 
strength is greatly reduced and a slight nick will deter- 



mine the point of fracture. Third, disfiguration of the 
parts is offensive to the eye and bespeaks slouchy or care- 
less workmanship. 

Locking Devices 

A fair proportion of accidents occurs to moving mech- 
anism through nuts or other threaded fastenings working 
loose. It is safe to say that several hundred patents 
have been taken out for nut-locking devices, but of this 
great number, a few only are of practical value and used 
to any extent. The castellated nut and cotter pin used 
of course with a drilled bolt or stud is one of the few 
devices that finds large application. It is generally used 
in automobile and aeroplane work. The spring locking 
washer is another good device. This is used where the 
fastening is of a permanent or semi-permanent character. 
Another method is to batter or hammer down the end of 
a bolt a little. This should be practiced only as a last 
resort or as an absolutely permanent job and must be 
carefully done, otherwise serious damage will result to 
the bolt and nut. It is sufficient to close one thread on the 
bolt for part of the circumference only. 

Turnbuckles are secured against turning or loosening 
by running a wire through the adjusting hole in the turn- 
buckle sleeve and carrying the wire back and binding i 
around the ends of the turnbuckle. 




The proper way to lock a turnbuckle 



C H.M'TKK XII 
ALIGNMENT 



Hv tin ti-nn aeroplane alignment is meant the art of 
truing "|> an aeroplane, and ailj listing tin- parts in tli.-jr 
proper relation to each other as designated in the ... r,. 
plane's spccilicatioiis. Tin- inln-rrnt stability, tin- sp, , ,1. 
th<- rate of climb, tin- ctfieiency. in short the airworthin. -ss 
of an aircraft depend in large measure on its correct align- 
nifiit. 1 ,, r this reason the importance of careful and 
rorro-t alignment cannot be overestimated. 

'I'ln instructions as gixcn in this chapter are not in- 
tend..! to be a complete and exhaustive treatise on the 
who], subject of aeroplane alignment, but are designed 
rather to give the beginner a good general idea of how 
the work is done. Thus with these instructions as 
ground work he can become proficient in the work after 
baring hail good practical experience in the hangars. 

The work of aligning an aeroplane divides naturally 
into several distinct and separate groups or divisions a. 
fuselage, b. horizontal and vertical stabilisers, c. landing 

d. center w ing section, e. wings, f. controls. 
.Iliiinmenl of futrlage. The fuselage is aligned be- 
fore leaving the aeroplane factory and normally this align- 
ment will last for some time. The fuselage alignment 
should be checked over carefully, however, after an aero- 
plane has been shipped in disassembled condition. Strains 
on the fuselage caused by rough handling, bad landings, 
etc.. will make it necessary to re-align it. 

H' tore attempting to align any part of an aeroplane 
the erection drawings should be referred to if available, 
and the directions furnished by the makers should be 
followed carefully unless the operator has had a great 
deal of previous experience upon the particular type of 
aeroplane to be aligned, and is familiar with better meth- 
ods of procedure than those recommended by the maker. 
In general the procedure in aligning a fuselage will be 
about as follows: A horizontal reference plane is usually 
specified by the makers in connection with the fuselage. 
Sometimes the top longerons are taken as this reference 
plane, in which case they are to be aligned horizontally, 
laterally, and longitudinally from a specified station to the 
tail post. Sometimes horizontal lines are drawn on the 
vertical fuselage struts, and the fuselage is so aligned 
that these lines all fall in the same horizontal plane. 

Alignment of Longeron* 

In the first case, after the fuselage has been placed in 
a flying position, the top longerons are aligned for straight- 
using n straight edge and a spirit level to aid in 
finally placing them laterally and longitudinally in a 
horizontal plane. 

303 



The longerons are next aligned symmetrically with re- 
spect tc, the imaginary vertical plane of symmetry through 
the fore-and-aft axis of the fuselage. There' are two 
general methods of doing this, as follows : 

I irst Method The center points are marked on all 
horizontal fuselage struts. A small, stout cord is stretched 
from the center of the fuselage none to the tail post and 
the horizontal bracing wires adjusted until the centers 
of the horizontal struts fall beneath this line. A small 
surveyor's plumb bob is held at different |minU so that 
the suspending cord just touches the fore-and-aft align- 
ing cord. The centers of the bottom horizontal struts 
should fall directly below the bob. 

Second Method A plumb line is dropped from the 
center of the propeller and from the tail |x>st and a string 
is stretched on the ground or floor between these two 
points. Plumb bobs drop|ied from the centers of the 
horizontal struts must point to this line. 

The whole fuselage alignment is checked to make sure 
that it agrees with the specifications. If the aeroplane 
has a non-lifting tail, it would be advisable as the next 
step to support the fuselage in such a way that the rear 
part (about two-thirds of the total fuselage length) re- 
mains unsupported, and then re-check the fuselage align- 
ment once more. 

All turnhuekles should then be securely locked and the 
fuselage carefully inspected. 

Horizontal and Vertical Stabilizers 

The vertical stabilizer is examined to see that the bolts 
holding it in place are properly drilled and cotter-pinned, 
also to see that it is set parallel or dead on to the direc- 
tion of motion. It is trued up vertically by the turn- 
buckles on the tie wires or brace wires connected to it. 
These turnbuckles arc then properly safetied. 

The horizontal stabilizer usually is braced with tie 
wires fitted with turnbuckles. By means of these its trail- 
ing edge should be made straight and at right angles to 
the horizontal center line of the fuselage. All bolts 
fastening the horizontal stabilizer to the fuselage should 
be inspected to make sure they are properly drilled and 
cotter-pinned. All turnbuckles should be safetied, as pre- 
viously shown. 

.Ilifinmrnt of landing gear or undrr-carriagr. In as- 
sembling an aeroplane which has been completely dis- 
mantled, the landing gear should be assembled to thr 
fuselage and aligned with it before the wings are at- 
tached. In assembling and aligning the landing gear, 
the fuselage should be so supported that the landing gear 



304 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



hangs free and the wheels do not touch the ground. 
The fuselage is placed in the flying position, or at least 
in such a position that the lateral axis is horizontal. 
There are three general methods of aligning the landing 
gear, as follows: 

First Method A small plumb is dropped from a poi 
on the fore-and-aft center line of the fuselage above the 
axle of the landing gear. A tack is placed in the exact 
center of the axle casing or a scratch is made on the axle 
at its center. The transverse tie wires are then adjusted 
until the tack or center line mark falls exactly below the 
plumb bob. The wires are made moderately tight. The 
exact degree of tautness required cannot very well be 
described; it is a matter of experience or personal instruc- 
tion. All turnbuckles are safetied and the landing gear 
inspected carefully. The strut fittings and the elastic 
shock absorbers should be inspected very carefully. 

Second Method The two forward transverse tie wires 
are adjusted until equal in length, then the rear trans- 
verse tie wires are similarly adjusted until they also are 
equal in length. All transverse tie wires are tightened 
equally and the turnbuckles safetied. The landing gear 
is then given a final inspection. 

Third Method The transverse tie wires are adjusted 
until the axle is horizontal as shown by a spirit level. 
This adjustment is made with the fuselage in the flying 
position or with the lateral axis horizontal. The trans- 
verse tie wires are tightened equally to the correct taut- 
ness, the turnbuckles safetied, and the landing gear in- 
spected as before. 

Center Wing Section 

Alignment of center wing section. The fuselage is 
first placed in the flying position, and the center wing 
section adjusted symmetrically about the fore-and-aft 
center line of the fuselage in plan. A tack driven in 
the middle of the leading edge of the center panel will 
then be directly above the center line of the fuselage. 
This is tested with a small plumb bob and checked by 
measuring each pair of transverse tie wires to see if the 
two wires of each pair are equal in length. 

The alignment for stagger is made by adjusting the 
stagger or drift wires in the fore-and-aft direction until 
the leading edge of the center panel projects the required 
distance ahead of the leading edge of the lower plane as 
given in the aeroplane specifications. This alignment is 
checked by dropping a plumb bob from the leading edge 
of the center panel and measuring forward in a hori- 
zontal plane from the leading edge of the lower plane to 
the plumb line. The adjustment for stagger fixes the 
rigger's angle of incidence. All turnbuckles are safetied 
and the alignment re-checked. 

Alignment of wing*. Before any attempt is made to 
align the wings the fuselage should be carefully inspected 
to make sure that it is properly riggeed and in proper 
alignment. Failure to do this may cause much delay and 
waste of time in aligning the wings. 

The next step is to make a general inspection of the 
wings, noting if all bolts and clevis pins are properly 
cotter-pinned. Note particularly the clevis pins where 
the interplane brace wires are fastened to the upper 
plane fittings. One of the largest aeroplane makers in 



tliis country puts these clevis pins in head down. In this 
position if the pins are not properly cottered, there is 
great danger of their working loose and dropping out, 
disconnecting the wires. Such matters are more easily 
remedied before the wings are aligned than afterwards. 

Loosen all wires between the planes including flying 
wires, ground wires, stagger wires and external drift 
wires. Examine the turnbuckles to see that the same 
number of threads show at both ends. If not, take the 
turn-buckle apart and remedy this. It will mean a sav- 
ing of time in the end if these matters are looked after 
before the actual truing up of the wings is begun. 

Flying Position 

Place the fuselage in the flying position as denned in 
the aeroplane's erection drawings. This may mean align- 
ing the top longerons or the engine bed or other specified 
parts laterally and longitudinally horizontal. This must 
be done carefully, using a good spirit level, because the 
wings are aligned from the fuselage upon the assumption 
that this flying position is correct. If it is necessary to 
get into the cockpit or in any other way disturb the 
fuselage during the alignment of the wings, make sure 
that the fuselage is still in the correct flying position be- 
fore proceeding further. 

Lateral dihedral angle. There are three common meth- 
ods of adjusting for lateral dihedral: 

Aligning Board 

First Method Aligning Board. 1 If an aligning board 
is available its use saves considerable time due to the fact 
that the rigger secures the lateral dihedral angle, straight- 
ness of wing spars, and correct angle of incidence near 
the wing tips all at the same time. The protractor level 
should read directly in degrees. Set this instrument at 
the number of degrees dihedral stated in the aeroplane's 
specifications. Place the aligning board parallel to the 
front spar (by measuring back from the strut fittings) 
and, keeping the flying and stagger wires loose, pull up 
on the ground wires until the bubble on the protractor 
level reads almost level. Since the aligning board is a 
straight edge it is easy to keep the front spar perfectly 
straight by glancing- beneath the aligning board occasion- 
ally. It should rest on at least three ribs, one near each 
end and one near the middle. The space between the 
other ribs and the aligning board should be slight. 




^Dihedral Board 

FIG. 34 Method of using short dihedral board 

Place the aligning board in front of and parallel to the 
rear spar. Adjust the ground wires until the rear spai 
is straight and the dihedral is slightly greater than called 
for in the maker's specifications. Check at the front spar. 
It will now be the same as the rear. If not make it so. 

i See note on aligning boards at end of this chapter. 



ALK.XMKN I 






In. r, Points of iiieiisiin-ment for wing alignment 

Now tighten ilow n on all flying wires except those to 
the overhang, if then- is overhang. Test each pair of Hy- 
ing wires for equal taiitn, ss by striking with the edge of 
the hand and watching their vibration. The loose win- 
has Ih, greatest amplitude of vibration. The lateral di- 
hedral should now be exactly as called for in the spcciti 
cations. 

After aligning both wings for dihedral as stated above, 
both wings will lie the same height if the fuselage is h\el 
laterally. Check the height of the wings by making the 
distance BA (see Fig. 35) equal to DC measured from 
the longerons opposite the butt ends of the front spars 
on the lower wing panels. V is a tack in the middle of 
the leading edge of the center section panel. With a 
steel tape measure the distance V'A and VC. These dis- 
tant is should be equal. 

Kijiially good results may be obtained by using a pro- 
tractor spirit level in conjunction with an accurate straight 
edge. 

Second Method If a good aligning board is not avail- 
able the string method may be used. Fig. 36 shows the 
arrangement of the string which should be .small, smooth 
and tightly drawn. 

K-.-p the stagger wires, flying wires and nose drift 
wires loose as in the first method. Increase the dihedral 
angle, by tightening the ground wires, keeping the panels 
straight by sighting. The greater the dihedral angle the 
'r the distance Y (see Fig. 36). The table below 
shows the variation for customary range of lateral di- 
hedral: 

TABLE FOR I. \TIKAI. DIHF.nRAI. ANGLES 
X 



Deg 


Inches Mist a nee from 
|Miint of support of 
string to eiel of spar 


Inches Distance from 
ml of spar vertically up 
to th- liori/ont il strinir 





100 





1 


100 


!% 


2 
3 

4 


100 
100 
100 


3% 
5% 

7 


5 


100 


8l Vi 


6 


100 


Ktyta 


7 


100 


U% 


8 


100 


'"% 


9 


100 


1J% 


10 


100 


17*, 




Fio. 30 Alternative nirUMKi of aligning for dihedral 

'I'lir distance X will probably not be exactly loo in. M 
given in tin- table, hut sin,-,- X and \ i, u . r , ..,. " jn ,|,,. ,,. 
proportion tlii.s i-, vrry simple. For example, tin- ili> 
tance X (convenient to m, asure) on a hipl.ine |,a\ i,,g a 

ieg. lateral dihedral angle may be, say { ft. i> in., or 
l.'iO in., which is one and one-half times 10(1 in. 

The table gives Y e|unl to S'/i in. for .S dcg. Our X 
i* one and one-half times the X in the table. Then our 
V must be one and one-half times :, i , in ( the Y given in 
the table), which equals ~~ ^ >.. which is the proper dis- 
tance up to the string when the wing has tin- cornet lat- 
eral dihedral. 

In determining the distance Y, always measure the 
vertical distance up to the string from near the inner edge 
of the wing panel, not from the center section panel. The 
correct lateral dihedral angle having been obtained, pro- 
ceed further as in the first method. 

Third Method On aeroplanes having sweep-buck the 
string method is rather difficult to apply. If an aligning 
board such as used in the first method is not available, 
then a .short dihedral hoard may In- made which will scric. 
Fig. 37 shows the construction and Fig. 31 the method of 

I ' 




Fin. :17 Short ililieilr.il Uwrd 



using such a board. It is plain that a separate board 
must be made for each aeroplane having a different di- 
hedral from the others at a flying field. Another disad- 
vantage of this board is the fact that it must IN- used IN- 
tween struts on the spars and is so short that it is apt 
to be affected greatly by unei|iial rib heights and any 
lack of straight nets in the spars. 

After obtaining the correct dihedral proceed as in tin- 
first method. 

Stiii/i/i-r is usually given in aeroplane specifications as 
a linear measurement in inches. The specifications will 



300 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



of 




C orH (w/iictnver method of measuring 
ffi* specifications Co// forlis the sfoyoer. 

FIG. 38 Methods of measuring stagger 

tell whether it is to be measured on a projection of the 
chord or as a horizontal distance. (See Fig. 38.) It is 
important to measure the stagger in the manner directed. 

The stagger of the wings is fixed at the fuselage by the 
stagger of the center wing section. Align for stagger by 
adjusting the stagger wires between interplane struts. 
Slight adjustments only should be necessary. Fig. 38 
shows the method. 

In exceptional cases the flying and ground wires, front 
and rear, nearest the fuselage, are used in adjusting the 
stagger, which is usually found to be correct, however, 
after slight adjustments of the stagger wires. 

Stagger is sometimes given as an angle of stagger in 
degrees. This can be converted into inches by the use 
of the lateral dihedral table on page 305. In this case AB 
in Fig. 38 corresponds to X in the table, and Y in Fig. 
38 will be proportional to Y in the table. For instance 
if AB in Fig. 38 is 50 in. in a given aeroplane, or one- 
half of X in the table, and the stagger is given in the 
aeroplane's specifications as 7 deg., then the amount of 
stagger Y (Fig. 38) would be one-half of the 12 3/16 in. 
given in Column Y in the table opposite 7 deg. 

Overhang. If the aeroplane has much overhang it is 
usually supported by mast wires above and flying wires 
below. See that the flying wires are loose. Tightening 
one set of wires against an opposing set throws undue 
stress in members. Tighten up on the mast wires until 
the overhang inclines very slightly upward. Now tighten 
up on the flying wires below until the spars are straight. 

The leading and trailing edges of all wing panels should 
now be straight. In case there should be small local bows 




Spirit Level 



Sfraight Ee/ye 

Fio. 39 Measuring angle of incidence with straight-edge and 
spirit level 




Straight Jye 

FIG. 43 Another method of measuring angle of incidence. 
It can also be done advantageously by using a straight edge in 
conjunction with a protractor spirit level 

in the spars, with a little careful adjusting of wires these 
can usually be distributed equally between the upper and 
lower wing panels so that their effect will be lessened. 
Fixing the lateral dihedral or the angle of incidence for 
either upper or lower plane automatically adjusts it for 
the other plane. 

Rigger's angle of incidence. Check the lateral dihedral 
to make sure that it has not been altered in making other 
adjustments. If it is correct, front and rear, and the 
spars are straight, then the angle of incidence should be 
correct all along the wing. Figs. 39 and 40 show two 
methods of testing this. If the set measurements A or B 
are known, the first method (Fig. 39) can be used. If 
the angle AOB is given in the specifications then the sec- 
ond method (Fig. 40) can be employed. Test the angle 
of incidence near the fuselage and beneath the interplane 
struts. 

Wash-out and wash-in. Due to the reaction from the 
torque of the propeller the aeroplane tends to rotate about 
its longitudinal axis. To counteract this the wing which 
tends to go down (sometimes referred to as the " heavy " 
wing) is drawn down slightly at its trailing edge towards 
its outer end, or in other words it is given a slight addi- 
tional droop at this point. This is usually referred to as 
a " wash-in." The wing on the other side of the machine 
is given a slight upward twist, or " wash-out at a cor- 
responding point. In single-engined, right-hand tractors 
wash-in is given to the left wing and wash-out to the right. 
To increase the angle of incidence the rear spar must be 
warped down by slackening all the wires connected to the 
bottom of the strut and tightening all which are connected 
to the top of the struts, until the desired amount of wash-in 
is secured. This process is reversed to secure wash-out. 

For purposes of increased stability wash-out is some- 
times given both wings although of course some lift is lost 
by doing this. If it is still desired to compensate for the 
reaction due to the propeller torque, more wash-out is 
given on one side than on the other. The side having the 
least wash-out then has wash-in relative to the other side. 

Over-all measurements. Tighten the external drift 
wires only moderately tight. The following over-all 
measurements should now be taken, using a steel tape (see 
Fig. 35): Make BA=DC and LH = MN. Then OA 
should equal OC and HE should equal EN. These meas- 
urements should be made at points on the upper wing 
panels as well as the lower, making eight check measure- 
ments in all. 

All turnbuckles are now safetied (Fig. 41). Make a 
general final inspection of the wings to make sure that 



ALKi.N.MI.N T 



.{07 




Block. 



*+ 



-' linliiiiln.il method ,if connc, tin^r aileron controls 

hat hern overlimkrtl. It mutt lie rrmrmbrrrd that 
in m,ikni<i on,- n-ljintmrnt other adjuttment* made pre- 
./-/ man '"' thrown tlit/litly off, to that u-hen the u-inyi 
are finnlli, aliened it it a good plan to check the lateral 
dihedral, .itn ; / ; /,-r, angle of incidence, etc., to make ture 
I tin t nil are correct. 

Contrail Aileront. Fasten the hand wheel, stick, or 
.shoulder yoke controlling the ailerons in its central posi- 
tion. If the ailerons have brace wires on each side (se 
anil these wires are supplied with turnbuckles, 
.straighten up the trailing edge by adjusting these wires. 
If the ailerons are connected as in Fig. !:! the trailing 
edj:.-s must l>, straightened as the ailerons are aligned on 
the aeroplane. 

Then- is difference of opinion about drooping the trail- 
ing edge of ailerons In-low the trailing edge of the plane 
to which they are fastened. At some fields the turn- 
buckles on the aileron control cables arc so adjusted that 
the trailing edge of the aileron lines up with the trail- 
ing edge of the wing panel to which it is hinged. At 
other fields, from ' s in. to :! , in. of droop is given the 
trailing edge of the aileron. Ix-cause it forms a part of a 
lifting surface and it is reasoned that. slack will IK- taken 
out of the lower control cables when the machine gets 
into the air. I'nless directed otherwise it perhaps is ad- 
visable to give little or no droop. 

The ailerons should work freely and respond quickly 
with no feeling of drag when the hand wheel is turned 




ToeA 

I 



/Vvfrvabr 



Sfrt/ffht Ed,. 
Teat for Srrotffttnttt 
r Tr>-ing an aligning board for itraightnriw 



>r the stick moved even very slightly. Improper coiling 
of rabies when a machine is dismantled will ruin tins 
ilitic.n .itMiut as quickly as anything ,-,,ii| ( |. c. ir< - must ! 
liken not to put too muc-li tension on the cables. The 
pulleys around which they run on- light, and not alw 
so strong as they might be. Cracked pulleys may so: 
times Ix- found on old macliin. s. 

Intcrplanc ailerons are adjusted so that both arc in the 
same plane when rontrol j s neutral. Tin- angle at whieh 
they are set must be given by the makers or d. t. rinin. -d 
by experiment and experience. 

Ktevatort. Fasten the bridge or stick control in its 
central position. Adjust the turnburkles on the control 
cables until the elevators are in tin ir ncutr.-il position and 
both are in tin- snme plane. Tighten the control cables 
enough to remove lost motion. 

liudden. Fasten the rudder footbar in its mid-posi- 
tion and adjust the turnbuckles until the rudder is in the 
neutral position, and the cables are tight enough to re- 
move lost motion. 

Both elevators :md rudders usually carry brace wires 
with turnbuckles which can be used in straightening their 
trailing edges. 

Notes on Aligning Boards 

To be useful an aligning I o.ird first of all must be true. 
Fig. 11 shows a method of testing such a board for 
straightness. (See A and B, Fig. 44.) Also by sup- 
porting the board as shown and setting the protractor lei i I 
at different degrees the protractor can be tried out. Ref- 
erence to the table for lateral dihedral on page :<<>;> shows 
the difference in thickness of the blocks for the different 
angles. The zero point may be tested by setting the in- 
strument at y.cro and supporting the aligning hoard on 
some surface known to !>r level. 

Tin inclin.ition for the board used- in the third method 
of aligning for lateral dihedral can be determined from the 
lateral dihedral table. Fifty inches make a convenient 
length for such a board, in which ease the Y (see Fig. 45) 
is just half of that given in the table for lateral dihedral 




I : 



Slum-ing series method of connecting ailerons in pair* 



Test of Proh+c/br U~/ 



Fio. 43 Alipninfr board us.-,! with Uble for lateral dihedral 

angles 



CHAPTER XIII 



CARE AND INSPECTION 

Cleanliness Control cables and wires Locking devices Struts and sockets Special inspection Lubrication 
Adjustments Vetting or sighting by eye Mishandling on the ground Airplane shed or hangar Estimating 
time Weekly inspection card form. 



Cleanliness. One of the most important items is clean- 
liness of all parts of the plane. After every flight the 
machine should be thoroughly cleaned. To remove grease 
and oil from the wings and covered surfaces, use either 
gasoline, acetone or castile soap and water. If castile 
soap cannot be obtained, be sure the soap used contains 
no alkali or it will injure the dope. In using the gaso- 
line or acetone, do not use too much or it will also take 
off the dope. A good way to use the latter is to soak 
a piece of waste or rag and rub over the grease or oil, 
theB wipe off with a piece of dry waste. When using 
soap and water be careful not to get any inside the wing 
as it is liable to warp the ribs or rust the wires. 

When mud is to be removed from the surfaces it should 
never be taken off while dry, but should be moistened with 
water and then removed. 

Other parts of the machine should be kept thoroughly 
clean to keep down the friction. 

Control cables and wires. All cables and wires should 
be inspected by the rigger to see that they are at the cor- 
rect tension. Also see that there are no kinks or broken 
strands in any of the cables or strands. Do not forget 
the aileron balance cable on top of the wings. When a 
wire is found to be slack do not tighten it at once but 
examine the opposing wire to see if it is too tight. If so 
the machine is probably not resting naturally. If the 
opposing wire is not over-tight then tighten the slack wire. 

All cables and strands and external wires should be 
cleaned and re-oiled about every two weeks. The oil 
should be very thin so that it will penetrate between the 
strands. 

Locking devices. All threaded fastenings and pins 
should be inspected very frequently to see that there is 
no danger of anything coming loose. 

Struts and sockets. Since the struts are compression 
members, largely, they should be examined on the ends 
for crushing and in the middle for bending and cracking. 

Special inspection. A detailed inspection of all parts 
of the machine should be made once every week. Usually 
there is an inspection sheet provided for this purpose. 
If no sheet is obtainable, then one should be made before 
the inspection is started. Make a list of all the parts to 
be inspected, starting at a certain point on the machine, 
and following around until that point is reached again. 
When each part or detail is inspected it should be checked 
on the sheet as defective or O. K. 

A good weekly inspection card form is given on the 
following page. 

Lubrication. Always see that all moving parts are 
working freely before a flight is made. This includes 
undercarriage wheels, pulleys, control levers, hinges, etc. 

308 



Adjustments. The angle of incidence, dihedral angle, 
stagger and position of the controlling surfaces should be 
checked as often as possible so that everything will be 
all right at all times. Alignment of the undercarriage 
should be made so that it will not be twisted and thus cut 
down the speed of the machine. 

I'etting or sighting by eye. This should be practiced 
at all times. When the machine is properly lined up, 
look at it and get a picture in your mind of just how it 
looks. Then when anything becomes out of line it can 
be easily detected without using any tools. See that the 
struts are in the same plane when looking at the front 
or side of the machine. The dihedral angle also can be 
checked by this method of sighting. Some flyers become 
so expert that they can check the alignment of the whole 
machine by eye. 

Distortion 

Always be on the lookout for dislocation of any of the 
parts. If any distortions cannot be corrected by adjust- 
ment of the wires, then the part should be replaced. 

Mishandling on the ground. Great care should always 
be taken not to overstress any part of the machine. Mem- 
bers are usually designed for a certain kind of stress and 
if any other kind is put upon them, some damage is likely 
to occur. When pulling an aeroplane along the ground, 
the rope should be fastened to the top of the undercar- 
riage struts. If this cannot be done, then fasten the rope 
to the interplane struts as low down as possible. 

Never lay covered parts down on the floor but stand 
them on their entering edges with some padding under- 
neath. Struts should be stood on end where they cannot 
fall down. 

Hangar. The hangar at all times should be kept in 
the best possible condition. Never have oily waste or 
rags lying around on the floor or benches, as these are 
liable to catch fire. No smoking should be allowed in or 
near the building. Do not have oily sawdust spread 
around on the floor to catch the oil but have pans for this 
purpose. 

In making replacements of defective parts, have a place 
for the old pieces. Never allow them to be put where 
they will be mistaken for new parts. 

Each tool should be kept in a certain designated place 
and when anybody borrows a tool, be sure that he puts 
it back where it belongs. 

Estimating time. When any repairs are to be made, 
learn to estimate the time required for the job. With a 
little practice this can be done very accurately. It may 
help sometime in making a report to an officer in charge 
as to when an aeroplane will be ready to go out again. 



AM) INSI'KCTIOX :,., 

Weekly Aeroplane Inspection Card --irult: 

I,,,/, /;,, It-. ''otters 

./.>,./, .V,, !/..*. StraightneM 

h:n,,in, \,, M,,k, I/,,,/, | 'Kt 

I .ft 

I his eM urn--! ! in. ill,- mil li\ I iel.l Inspector for /;/< r. 

I-MTJ machine iiiuliT his charge, sign.-,! |, v him. ami must I,, ,l.,Mn^ 
tiin.nl oxer t,, II,,. Chirf Inspector as soon $ i,,.,,l, out. 

1 1 inc. .-,ssci,il.|\ (lubricate with graphite grease) 

l.niK/in,/ ijrar: .. j|y . 

Wire Iriisi.in Wear 

Wire terminals Hinge pins :,u<l .-..It. -rs 

Strut sockets (nuts, liolts) Control win- connection (must) 

Loose spokes K rayed control wire (wheel) 

\\lesgreascd (pulleys and guides) . 

irity .if wheels to a\lc Control wirrs frnycl nt any part of thrlr Irnfrth 

Shix-k .iliMirU-r riihlx'r iniivt Ix- rrplacl t iin.-r. 

'1'irr iiitl.iti.in l'iill.-ys 

/'r../.. II. r Crraxrd 

(..n.liti.m ,,f I,],,,!,.. Vrrr runninfr . 

Hnl. .i-.-riiil.ly (I.,,!!-, w.i.hrr.. .-..ttrrs) \i\fiM Herons upjicr ... knrrr.. 

urity to shaft '-<" "Herons upjier lower 

Tliru.st Fiurlayr rrar interior: 

fut,t.,,l, nnit: Wirr Inisions 

r,-iisi,,ii fusrliip. bracing ' '"(-rong 

Tension and t. -riiiinals winjt drag hracinjf ttings 

Knpine !<! and Ix.lts \li){niiient 

,,,,,,: Stahilizrr: 

I , , , , Bolts nuts, cotters, braces 

It.nliati.r full rrrliral ft>: 

/;,,,,. Holts, nuts, cotters, braces 

Valves K mldrr : 

Intake clearance Hinfre assembly 

I \lmiist olrarnnre Security 

Spark plufrs Wear 

Clean Hlnjfe pins and cotters 

( iiip Control win- connections 

-l.uretor Mat 

S<-curity to manifold l-'oothar 

Bracing Kmyed control wire 

Manifold joints N'ote: Control wires frayed at any point of their length 

Oil t<i>ttm: IMllst |K> repl-l once. 

kage Pulleys 

( )il (grade) 

Oil reservoir full Frpe r ">nlng 

Elrralort: 

Hinge assembly 

6 ' 



Distributor lx>anl Wear 



Breaker point clearance HtafB pta rf 0*toW ...... 

I rans,,,,ss,on (drive) wear Contr((| wjn . ,.., ,,, 

tlr control: Control wire connections post 

1'iillcys Frayed nintrol wire 

Wiring Note: Control wires frayed at any point of their length 

Bell cranks and connections must be replaced at once. 

ir tytttm : Pulleys 

Tank Creased 

Gasoline leads and connections Free running 

1'iinip Right elevator 

Gasoline in tank full Left elevator 

j,>inli: Tail tkiil: 
' I-ower wing right Skid 

Ix>wer wing left Fittings 

I'pprr wing right Shock absorber 

I'pper wing left Control*: 

icirrt: (tension, terminals clevis pins, cotters, safety Free and proper operation (lubricate with graphite 

wires) (frease) 

Flying wires right wing Elevator 

I h ing wires left wing K udder 

Landing wires right wing Aileron 

Landing wires left wing ./ li<;nmrn/ nf rittirr markinr : 

Wires, fittings, turnbuckles, cleaned and greased 

firtin,!*: (bolts, nuts, cotters) 

Right wing, upper lower 

I-eft wing, upper lower (Signed) Field Inspector. 



CHAPTER XIV 



MINOR REPAIRS 

Patching holes in wings Doping patches Terminal loops in solid wire Terminal splices in strand or cable Sol- 
dering and related processes Soft soldering Hard soldering Brazing Sweating procedure in soldering 
Fluxes Melting points of solders. 



The materials used in patching holes in linen-covered 
surfaces is unbleached Irish linen, the same kind as used 
in covering the wings. The material must be unbleached 
or it will not shrink the required amount. Generally the 
kind of dope used is Emaillite dope, although the acetate 
or nitrate dopes could be used. The dope should be ap- 
plied in a very dry atmosphere or on a sunshiny day at 
a temperature not less than 65 deg. F. A brush or a 
piece of waste may be used to apply the dope. 

In patching a hole the first thing to be done is to clean 
the surface of the old dope. To do this, fine sand paper 
may be used or acetone, gasoline or dope. In using the 
sand paper, care should be taken not to injure the cover- 
ing. When using the acetone or gasoline, it should be 
put on the surface, allowed to stand for a while to soak 
up the old dope, then scraped off. The same method is 
applied when using dope to clean the surface. 

After the surface is cleaned, the edges of the hole 
should be sewed if it is of any considerable size. To do 
this sewing linen thread and a curved needle are used. 
The stitches should not be closer together than !/> in. and 
far enougli back from the edge so that there is no dan- 
ger of their tearing out. With a small hole, such as a 
bullet hole for instance, it is not necessary to do any 
sewing. When the hole is several inches square, a piece 
of unbleached linen should be sewed in to give a body for 
the top patch so that it will not be hollow in the center 
after it is dry. The sewing up of holes should be done 
after the surface is cleaned so that any slackness may be 
taken up before the patch is applied. 

After sewing is finished the patch is cut. It should be 
made about 1 to 2 in. larger on each side than the hole. 
The edges of the patch must be frayed for about 1/4 in., 
this being done to prevent them from tearing easily. 

Dope should now be applied to the wing. Generally 
several coats are put on so that there will be a sufficient 
amount to make the patch stick well. After the last coat 
is applied the patch should be put in place immediately 
before the dope has a chance to dry. Any air bubbles and 
wrinkles should now be worked from under the patch by 
rubbing with the fingers, and more dope put on top of 
the patch. Usually there are six or seven coats of dope 
applied on top of the patch, allowing time for each coat 
to dry before another is applied. 

Any small amount of slackness in the patcli will prob- 
ably be taken out as the linen shrinks. If the patch is 
hollow after the dope is thoroughly dry, however, it is not 
a good patcli and should be removed. A good patch 



310 



should be tight around the edges as well as in the center 
over the hole and should contain no creases or air bubbles. 

Terminal Splices 

A loop or splice must be formed in the end of every 
brace wire or control cable where it is attached to a strut 
socket, turnbuckle, control mast, or other form of term- 
inal attachment. The manner of making the loop or 
splice in the wire will vary according to the type of wire 
or cable used. The terminal in the end of a solid wire 
is made in the manner shown in Fig. 33. 

There are several points to be observed in making tin's 
type of terminal splice, as follows: (a) The size of the 
loop should be as small as possible within reason, as a 
large loop tends to elongate, thus spoiling the adjustment 
of the wires. On the other hand, the loop should not be 
so small as to cause danger of the wire breaking, due to 
too sharp a bend, (b) The inner diameter of the loop 
should be about three times the diameter of the wire, and 
the reverse curve at the shoulders of the loop should be 
of the same radius as the loop itself. The shape of the 
loop should be symmetrical. If the shoulders are made 
to the proper radius there will be no danger of the fer- 
rule slipping up towards the loop, (c) When the loop 
is finished it should not be damaged anywhere. If made 
with pliers there will be a likelihood of scratching or 
scoring the wire, which would weaken it greatly. Any 
break or score in the surface coating of a wire destroys 
the protective covering at that particular point and the 
wire will soon be weakened by exposure. A deep nick 
or score would greatly weaken the wire and eventually 
result in breakage at that point. 

Splicing a strand or cable. The splice in the end of a 
strand or cable is entirely different from the terminal 
of a solid wire. The end of the strand is led around 
a thimble and the free end spliced into the body of the 
strand or cable just below the point of the thimble. Such 
a splice is afterward served with twine, but the serving 
should not be done until the splice has been inspected 
by whoever is in charge of the workshop. The serving 
might cover bad workmanship in the splice. 

Soldering. Terminal loops or splices in solid wire and 
also splices in the ends of strand or cord are sometimes 
soldered after being formed. There are some objections 
to soldering at these points, however, as outlined on page 
301. The ensuing instructions for soldering work will 
prove valuable in case where this method of securing a 
terminal splice is considered desirable. 



I: 



MINOR R I.I'. MRS 



.-ill 



Jinninif uf m ft alt hi/ 3<iltirrin</ anil rrlatnl 
There are several inrtli<Mls of joining metals tojji -tlu-r by 
alloy-, which nit-It at n lower ti inpcr.itiirc than tin- metals 
to IK- joined. These processes differ in tin- allov s u-. .1 
anil in tlit-ir melting temperatures. Tin \ in ili\ iilrtl intn 
four classes, 11 follows : 

Soft Mlllll rillU'. Tills 111. til. M! is till" I'lll Used 111 

till smithiiii; generally, where tin- solder is null, il hv 
iiu-.-iiis ol .-i hut soldering coppi r n\rr thr surfaces to be 
joinril. 'I'lii solilrr nsi d in this process has a low melting 
point. 

Mini soldering. This method is usually used m 

jcwclrv w.irk :IIH| in tin- ,-irts. when- :i higher t. mperatiire 

must In withstood. Tin- joining metal in this case has a 

iniirli higher MM ItniLT IMIIIII th tn soft soldi r. and must be 

I with .1 blow torch to mnkc it flow. 

Hra/ini;. This process differs from hard solder- 
inir onlv. in the t'.-irt that the joining metal has a still 
higher melting point. It is used principally in motor- 
cycli . bievclc anil automobile construction, where greater 
strength is required. 

>w . at inc. Tins is a process used where tin- \- 
to lie joined can tirst lie fitted together, then individually 
d with solder, then clamped together and heated until 
the solder Hows md cements them solidly together. This 
method allows for a more perfect joint being made. The 
more accurately the parts are fitted together the stronger 
the union will lie. Also, the thinner the coat of solder- 
ing material, within reasonable limits, the stronger the 
joint. 

All of the above methods are used more or less in aero- 
plane construction and maintenance, but the one that is 
most generally used is the first, or soft-soldering method. 
Cle-niliness is of prime importance in making joints or 
fastening by any of these methods. In soldering, the 
first step is to see that the soldering copper is clean and 
well tinned, for this may determine the success or fail- 
ure of the job. There are several ways of cleaning and 
tinning the soldering copper, but the one recommended 
b to heat the copjxr to about 600 deg. F., then dip the 
point (jiiiekly into a cup or jar containing ammonium 
chloride (Nil, (1) and granular tin or small pieces of 
r. If any considerable amount of work is to be done, 
an earthen jar or a teacup can be used, and kept partly 
tilh d with this mixture. 

Tinning Soldering Coppers 

Another way of tinning the soldering copper is to make 
prcssion in a piece of sheet tin and place in it a small 
lii.intity of soldering flux together with a piece of solder. 
the copper until bright, heat it to about 6OO deg. F., 
and then move it around, while hot, in the depression in 
the tin until it becomes coated with molten solder. It will 
now IM- ready to use. 

The n,\t step is to clean thoroughly the parts to be 
joint d. using fine emery cloth, sandpaper or a scraper. 
If the parts are of raw material, sandpaper will do, but 
if they are old parts which previously have been exposed. 



or if a In i\ y ovule has formed, the surfaces to be soldered 
should U iihd or script d until jicrfectlv bright and clean. 
The , ! rface should then IK- covered with soldering 

fluid or one of the iii.inv soldering pa- 

II' it the soldi ring copper to about tiOO deg. F., and 
touch it to (he solder, being careful to get only a small 
amount of solder on the copper. Hub the copper over the 
surfaces to lie joined until n bright, even coating of solder 
clings to the surfaces. Place the pieces together and 
.ntil the solder flows, using the hot copper to furnish 
the necessary heat and adding more solder as n. 
Care irtust be taken not to overheat the pieces at the joint. 
as this has a ten.!- m v to weaken the metal at that point 
and may cause trouble. 

The same general procedure as the above is followed 
for hard soldering, with the exception that a higher tem- 
perature must be applied. 

Fluxes 

1 luxes arc used in soldering to prevent, so far as pos- 
sible, the formation of oxides on the heated surfaces, and 
to flux off those that may have formed. Acid fluxes are 
the most effective and on iron or steel are practically 
>ary. The objection to their use is that unless the 
parts are thoroughly cleaned after soldering the acid in 
the flux attacks and corrodes them. 

In the case of stranded wires or cables the flux will 
penetrate into the minute spaces between the strands and 
will IK- extremely difficult to remove or neutralize, even 
when the cable or wire is washed with or dipped in an 
alkaline solution, such as soap or soda water. 

Some of the fluxes in general use are: 

Xinc chloride (/n Cl), corrosive 

Dilute muriatic acid (H Cl), corrosive 

Resin, non-corrosive. This is satisfactory for tin, but 
will not work on galvanising. 

Hi-sin and sperm candle melted together make a fair 
non-corrosive paste. For either tin or galvanising use 
three parts resin to one part sperm candle. Sometimes 
licttcr results are obtained on dirty surfaces by adding 
one part alcohol to this mixture. 

Mfllinij point* of tcAdert. The melting points of sol- 
ders composed of tin and lead in various proportions are 
as follows: 



Proportion 


Mrllinp 
Point 


Tin 


Lead 


1 part 
1 part 
1 part 
\\ parts 
6 parts 


.'i parts 
5 parts 
1 part 
1 part 
1 nrt 


44H rfrjr. F. 

All <lr(T 1 
llr,r. K. 

340 drg. K. 
ffTRdr*. F. 



A com|H>sition of 1 to I is most commonly used for tin- 
smithing. For electrical work where the solder i* used 
in the form of wire, a proportion of \\'. 2 to I or to 1 is 
used. 



CHAPTER XV 
VALUE OF PLYWOOD IN AEROPLANE FUSELAGE CONSTRUCTION 

BY LIEUTENANT STEFANS D'AMico, 
Italian Aviation Mission. 



Recently aeroplane construction has undergone some 
very radical changes, in part due to the exigencies caused 
by the war, in part to the natural tendency to make a 
more and more organic machine out of the aeroplane, by 
employing in its design the same fundamental principles 
which guide the design of modern mechanical devices. 

Often these two conditions have coincided so as to ex- 
pedite the ultimate result. 

Of all the parts of the aeroplane, the fuselage has un- 
doubtedly undergone the most radical change. On the 
one end the development of aerodynamics and the neces- 
sity to get from the aeroplane the greatest speed coupled 
with the greatest mobility have changed its form and pro- 
portions, and on the other hand modern and more practical 
principles of construction have completely altered its 
make-up. 

Until recently, the fuselage in all aeroplanes consisted 
of a frame suitable to withstand the stress and this was 
then covered with linen properly varnished. 

The frame consisted of four longerons, running length- 
wise of the fuselage with struts and steel wires latticing 
in both planes, vertical and horizontal, so as to divide it 
into panels. 

The joints of the struts to the longerons were metallic 
fittings and the proper tension in the latticing was obtained 
by the use of turnbuckles. 

The solid resulting by this method is capable of with- 
standing the stresses imposed from all sides but is a com- 
plicated structure, since it is made up of a large number 
of parts, has a great many wire connections, and must be 
frequently adjusted to the proper shape by giving the 
wires the proper tension. 

The fuselage, because of the frequent landing, is sub- 
jected to violent dynamic stresses causing a stretching in 
the tension wires, a disarrangement of the whole structure, 
as well as a stretching of the linen covering. The ele- 
ments also influence to a great extent the stretching of 
the covering and this impairs to a large degree the aero- 
dynamic property of the machine. 

The war then has developed it to such an extent, that 
while the fuselage has forfeited a little the advantage in 
weight, the machine has gained in life and efficiency. 

At any rate, the abandoning of such a construction was 
desirable because of the ever-increasing scarcity of metal 
fittings of alloy steel, as well as for the excessive cost and 
the lack of labor which is felt more each day. 

The use of plywood, which had already been used in 
large quantity in the construction of hydroaeroplane boats, 
appeared to be very appropriate since it eliminated a 
great many of the disadvantages enumerated. 

In as much as the only advantage of the old type was 



its lightness, all the builders tried very hard to make the 
best use possible of the material in order to eliminate this 
disadvantage which, in some cases, is considerable. 

In its most common form the modern fuselage is made 
of four longerons, tied together by means of diaphragms 
and then covered by plywood. The shearing stresses are 
taken care of by stiffening the outside covering with ribs 
of wood. 

The transverse stiffness is attained by means of trans- 
verse diaphragms in the rear, while in the front, where 
this is not possible, since the passengers have to be accom- 
modated as well as the tanks, motors, etc., this is done in 
a special way for each case, utilizing to the best ad- 
vantage the space resulting in distributing the various 
parts of the plane. The plywood is made to resist the 
moments due to deflection and principally shearing 
stresses. In this way the material is used to its full 
extent and its strength utilized to the best advantage. 
Therefore, since the material is used to its full value, the 
construction becomes light. 

The maximum strain on the fuselage comes on it when 
the tail skid strikes the ground. The maximum reaction 
will naturally depend on the total load P, which comes on 
it at this point and in computing, it is customary to con- 
sider this as double; that is 2P. (Fig. 1 and Fig. 2.) 

Therefore, at the section X distant from the point where 
the load may be considered as applied the moment. 
> MX = JP.X 

From this moment must be deducted the moment due to 
own weight of the fuselage so that the resulting expres- 
sion will be 

M'x=ZPx P'x. 

In its vertical direction the fuselage suffers a deflecting 
moment due to the compound load coming on the rudder. 

If this force be denoted by P" then Mx"~P" O -f c ) 
in which C is the distance from the axis of the tail and the 
center of pressure of the surface which makes up the rud- 
der. 

Considering the ordinary quadrangular form of fuse- 
lage, the distance Hx between the centers of gravity of 
the upper and lower longeron of the section H'jc of the 
longerons may be considered variable and following the 
linear law. So that: 



hx = ho 



&i ho 



oc x; oc = 



I 



Also in the horizontal section the distance A.r between 
the centers of gravity of the sections of the longerons may 
be considered in the same way as varying with straight 
line law. 



312 



PLYWOOD IN .\F.KoiM..\M. PUSELAGI CONSTR1 CTIOH :n.. 





Imill 
or inlrrior 



Cfou 







r.in~MTsc jririli-r >r<-ti<uis Imill fur llnrriiu of 
Naval Const ruction and Kepair 




^ 



Ti-stinjr I'rrsv in 
IjilMirntory 




Knjrinc Ivnrrrs for LiU-rlv inoliirrd DrMnvi- 
land lours 





Cowling and iiftcr-deck covering, built of p1jr-wmxl, for Dcllnvil/ind Koura. 





Photo, rourtnjr of Ib* Dodf* Mf( <' 
Interiors of aeroplane ronstrurtion rooms in an American factory 



314 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



Therefore in the same way we would have 
Ao 

2 Wx [Ao 



I 



r -I 

J = 

L # J, 



2 



Therefore at the longeron, with the greatest stress we 
will have the following united stress 

M'x M"x 

So = 8, + S 2 = - + - 

2Wa[ho+*x] 2 Wx [Ao + j8] 
from which would follow 

M's M"x 



28o [Ao + ccj-] 28o[Ao + /3x] 

If we fix So from the quality of the wood employed, and 
the factor of safety sought, the values <x, /8, Ao, ho will 
also be determined so that the required section of the ma- 
terial will be obtained. 

In order to find this section it is necessary to determine 
to what extent the plywood covering helps to resist the 
stresses. 

Tests which have been made have shown that the sec- 
tion Wx may be considered as made up of the longeron 
m, n, r, s and of a portion A, B, C - - A, D, E of the cov- 
ering working in conjunction with the longeron itself and 
utilizing DE and BC may be considered equal to 20.S, 
where S is the thickness of the plywood. (Fig. 3.) 
. : . Wx may be obtained from the formula 

2 

Wx=[h XI] +2X 20.5 

In calculating the shearing stresses it is best to plot 
them. This evidently will depend on the distribution of 
the strains along the fuselage. Having once determined 
from such diagrams the value of the reaction T, and the 
sectional area on which this acts, it may be considered 
that one-half of this reaction will be taken care of by the 
plvwood acting in tension and the other half by the diag- 
onal bracing at the sides which stiffens the structure. 

Therefore the stress on the plywood will be: 



8 = 



h [2 X S] 

For the stress in the diagonals, it will be easy to find the 
value along the diagonal in compression which we will call 
7\ (this value being for both diagonals). 

The minimum moment of inertia will be (Fig. -1) 

-2 
S 

Ixo = Ix 
A 

where S is static moment of the section with respect to 
XX, and A the area of section of the diagonal as well as 
that of the plywood acting with it. 

The diagonals may be considered as being completely 
fixed at both ends. Therefore it will be easy to determine 
the stress at the proposed section. 

The more detailed and exact is the analysis of the 
stresses made, the more advantageously will the material 
be utilized resulting in a great saving of weight. 

The plywood fuselage which has already found com- 
plete use in the small and medium sized machines has en- 
countered some difficulty in the large machines and this 
because of the large resulting weight. However, it may 
be foreseen that in the very near future, these difficulties 
will be eliminated. 

Recently tests have been conducted on fuselages made 
of wood, in which the longitudinal longerons running the 
full length of the fuselage have been eliminated as well as 
the stiffening ribs. 

Such a fuselage would be made by moulding on mould 
representing the fuselage very thin sheets of wood with 
fibre running perpendicular to one another, and then re- 
moving the shell from the mould when completed. 

These tests have already given good results and it 
seems as though they will lead to a practical result which 
would bring a great advantage in weight. 



s. 

a 

S 



- 

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< 
J 

g 



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_- r. 

1 i 

j. 



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i ; 



\ 

~ 

X. 

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J -,,...!,,,; 

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M -Ml I 
P-"l' 

i |MW| 

"|'J|| 



UI.JJ ,., 

mi 

ui. 

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u,.^,., 4W , 

- 

iii"* 

>UI 

lUt. 

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ui nj j*d 

qi qi 

mnat|x*in 

01 !|J,, n 






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ill. 

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- >, 

in* 



i; 'no jad -q> 



!!!! 1 } ] | 



! i ! i || < ! i i u sn n 

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?=>. q - ? AI. 

2 = * 



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*! O. l - - r 
i - <o c 



8 



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if 

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I I II MS} !! !S! S! 



g 

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g 1-3 

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sf 



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33353333S 3 



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3 3 3 3 33 553 



25 



335335333 S S 35 



as s 



3 3| 



- 55 - 



* ' 

* *\ 






~ ? 



^ 

"i * 
fc 



a 

M 


* S. = 

-*. 

tc c 

ij I 

T3 

e 5 ~ 
J*j 



* 



fllJI 



11 



s- 



























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J : 






\ : 






f 


: 








^ 
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c 


jf := 

^ c 


!?^- 




^ 

(B ^^ ^ 


- 
| 


2 C 


i 

>. 


i- ! l 


H 
i ? 




t = S S 

-=.= = 

r c - 

fe 2 - 


V 

' 
3 


1 


7 
^ 
- r 
s t 

f ^ 


lit 

1 :? 


scnrjrn 
MM li.i 






3 x - 
~ 2 S 

!-_ 
-^ s 



J :| * z 2 s 

i = * t * rf 

ITS 5 s-t-l 

S B.S 55^-3 - 



b.2 S o^ii 

.^i2*j<_^ 



III 



CHAPTER XVI 
NOMENCLATURE FOR AERONAUTICS 



AERODYNAMICS The science which treats of the air or 
other gaseous bodies under the action of forces and 
of their mechanical effects. 

AEROFOIL A thin wing-like structure, flat or curved, de- 
signed to obtain reaction upon its surfaces from the 
air through which it moves. 

AERONAUTICS That branch of engineering which deals 
with the design, construction and operation of air 

craft. 

AILERON A movable auxiliary surface used for the coi 
trol of rolling motion of an aeroplane, i. e., rotation 
about its fore and aft axis. 

AIRCRAFT Any form of craft designed for the navi- 
gation of the air; aeroplanes, balloons, dirigibles, 
helicopters, kites, kite balloons, ornithopters, gliders, 

etc. 
AERODROME The name usually applied to a ground and 

buildings used for aviation. 

AEROPLANE A form of aircraft heavier than air, which 
has wing surfaces for sustentation, stabilizing sur- 
faces, rudders for steering, power plant for propul- 
sion through the air and some form of landing gear; 
either a gear suitable for rising from or alighting on 
the ground, or pontoons or floats suitable for alight- 
ing on or rising from water. In the latter case, the 
term " Seaplane " is commonly used. (See defini- 
tion.) 

p us her A type of aeroplane with the propeller or pro- 
pellers in the rear of the wings. 
Tractor A type of aeroplane with the propeller or 

propellers in front of the wings. 

Monoplane A form of aeroplane whose main sup- 
porting surface is disposed as a single wing extend- 
ing equally on each side of the body. 
Biplane A form of aeroplane in which the main sup- 
porting surface is divided into two parts, one above 
the other. 

Triplane A form of aeroplane whose main support- 
ing surface is divided into three parts, superimposed. 
Multiplane An aeroplane the main lifting surface of 
which consists of numerous surfaces or pairs of su- 
perimposed wings. 

One and One-Half Plane A biplane in which the 
span of the lower plane is decidedly shorter than 
that of the upper plane. 

Flyiny Boat An aeroplane fitted with a boat-like hull 
suitable for navigation and arising from or alighting 
on water. 
Seaplane An aeroplane fitted with pontoons or floats 

suitable for alighting on or rising from the water. 
AIR POCKET A local movement or condition of the air 

316 



causing an aeroplane to drop or lose its correct atti- 
tude. 

AIR SPEED METER An instrument designed to measun 
the velocity of an aircraft with reference to the air 
through which it is moving. 

ALTIMETER An instrument mounted on an aircraft to 
continuously indicate its height above the surface of 
the earth. 

ANEMOMETER An instrument for measuring the velocity 
of the wind or air currents with reference to the 
earth or some fixed body. 

ANGLE OF ATTACK The acute angle between the direc- 
tion of relative wind and the chord of an aerofoil, i. e., 
the angle between the chord of an aerofoil and its 
motion relative to the air. (This definition may be 
extended to any body having an axis.) 
Best Climbing The angle of attack at which an aero- 
plane ascends fastest. An angle about half way be- 
tween the maximum and optimum angle. 
Critical The angle of attack at which the lift is a 
maximum, or at which the lift curve has its first 
maximum; sometimes referred to as the "burble 
point." (If the lift curve has more than one maxi- 
mum, this refers to the first one.) 

Gliding The angle the flight path makes with the 
horizontal when flying in still air under the influence 
of gravity alone, i. e., without power from the en- 
gine. 

Maximum The greatest angle of attack at which, for 
a given power, surface and weight, horizontal flight 
can be maintained. 

Minimum The smallest angle of attack at which, for 
a given power, surface and weight, horizontal flight 
can be maintained. 
Optimum The angle of attack at which the lift-drift 

ratio is the highest. 

ANGLE OF INCIDENCE (Rigger's Angle) The angle be- 
tween the longitudinal axis of the aeroplane and the 
chord of an aerofoil. 

APPENDIX The hose at the bottom of a balloon used for 
inflation. In the case of a spherical balloon it also 
serves for equalization of pressure. 

ASPECT RATIO The ratio of span to chord of an aerofoil. 
AVIATOR The operator or pilot of heavier-than-air craft, 
This term is applied regardless of the sex of the 
operator. 
AVION The official French term for military aeroplane; 

only. 

AXES OF AN AIRCRAFT The three fixed lines of refer- 
ence; usually passing through the center of gravitj 
and mutually rectangular. The principal axis in : 



NO.MKM I.ATl ]{K 10R AKKONAI Tit s 



817 



forr .-Hid aft direction, iisuallx parallel tu (lit- axis of 
tin propeller and in tin- plane of s\ mmetri . is tin- 
Longitudinal Axis or the lor. and Alt Axis The 
axis perpendicular to this anil in tin plain of ,\m 
nietry is the Vertieal Axis; the third axis perpendicu- 
lar to the other two is the Lateral Axis, also called the 
Tr IIISM rse Axis or the Athwartship Axis. In miithe 
niatieal diseiission the first of these axes, drawn from 
Iron! to nar is called the \ Axis; tin- si rond, drawn 
upward, the / Axis; and the third, forming a " left- 
liandi-d " s\ stem, tin Y Axis 

B.U.\MMI < ovnioi. Si HFACE A type of surface se- 
etired liy adding area forward of the axis of rota- 
tion. In an airstrcam a force is excrtid on this 
.id ! d an a. tending to aid in the movement about the 
axis. 

H\i \NIIN.. I LAPS (See AILERON.) 

ISwinSKT A small balloon within the interior of a 
balloon or diri^ihle for the purpose of controlling 
the ascent or de.sci nt. and for maintaining pressure 
on the outer envelope so as to prevent deformation. 
The ballonet is kept inflated with air at the required 
pressure, under the control of a blower and valves. 

BALLOON A form of aircraft comprising a gas bag and 
a basket and supported in the air by the buoyancy of 
the gas contained in the gas bag, which is lighter 
than the amount of air it displaced; the form of the 
gas bag is maintained by the pressure of the contained 
gas. 
Barrage A small spherical captive balloon, raised as a 

protection against attacks by aeroplanes. 
('attire A balloon restrained from free flight by 

means of a cable attaching it to the earth. 
Kite An elongated form of captive balloon, fitted with 
tail appendages to keep it headed into the wind, and 
deriving increased lift due to its axis being inclined 
to the wind. 
Pilot A small spherical balloon sent up to show the 

direction of the wind. 

Soundiny A small spherical balloon sent aloft, with- 
out passengers, but with registering meterological in- 
struments for recording atmospheric conditions at 
high altitudes. 

BALLOON DIRKIIBLE A form of balloon the outer en- 
velope of which is of elongated horizontal form, pro- 
vided with a car, propelling system, rudders and 
stabilizing surfaces. Dirigibles are divided into 
three classes: Rigid, Semi-rigid and Non-rigid. In 
the Rigid type the outer covering is held in place 
and form by a rigid internal frame work and the 
shape is maintained independently of the contained 
gas. The shape nnd form of the Semi-rigid type is 
maintained partly by an inner framework and partly 
by the contained gas. The Non-rigid type is held to 
form entirely by the pressure of the contained gas. 

HW.LOON BED A mooring place on the ground for a 
captive balloon. 

BALLOON CLOTH The cloth, usually cotton, of which 
balloon fabrics arc made. 

BALLOON FABRIC The finished material, usually rub- 
berized, of which balloon envelopes are made. 

BANK To incline an aeroplane laterally, i. e., to rotate 



it al'out the fore-and-aft axis when making a turn. 
Right li-ink is to incline the aeroplane with the right 
win^r down. Also usi d as a noun to di si-rilie tin- 
position ni an aeroplane when its lateral axis is in- 
clined to the horixontal. 

BAROGRAPH An instrument for recording xariatmns in 
barometric pressure. In aeronautics the charts on 
which the records are made are prepared to indicate 
altitudes directly instead of barometric pressure, in- 
asmuch as the atmospheric pressure varies almost 
directly with the altitude. 

BAROMETER An instrument for measuring the pressure 
of the atmosphere. 

BANKET The i-ar suspended beneath the balloon for 
passengers, ballast, etc. 

BIPLANE (See AEROPLANE.) 

BODY (or AN AEROPLANE) A structure, usually < n 
closed, which contains in a streamline housing the 
powcrplant, fuel, passengers, etc. 

Fuirlage A type of body of streamline shape carry- 
ing the empannage and usually forming the main 
structural unit of an aeroplane. 

Monocoque A special type of fuselage constructed of 
metal sheeting or laminated wood. A monocoque is 
generally of circular or elliptical cross-section. 
\acelle A type of body shorter than a fuselage. It 
does not carry the empannage. but acts more as 
streamline housing. Usually used on a pusher type 
of machine. 

Hull A boat -like structure which forms the body of 
a flying-boat. 

BONNET The appliance, having the form of a parasol, 
which protects the valve of a spherical balloon against 
rain. 

BOOM (See OUTRIGGER.) 

BOWDEN WIRE A stiff" control wire enclosed in a tube 
used for light control work where the strain is com- 
paratively light, as for instance throttle and spark 
controls, etc. 

BOWDEN WIRE GUIDE A elose wound, spring-like, flex- 
ible guide for Bowden wire controls. 

BRIDLE The system of attachment of cables to a balloon, 
including lines to the suspension band. 

BULLS EYES Small rings of wood, metal, etc., forming 
part of balloon rigging, used for connection or ad- 
justment of ropes. 

BURBLE POINT (See ANGLE CRITICAL.) 

CABANE (OR CABANC STRUT) In a monoplane, the strut 
or pyramidal frame work projecting above the body 
and wings and to which the stays, ground wires, 
braces, etc., for the wing arc attached. 

In a biplane, the compression member of an auxili- 
ary truss, serving to support the overhang of the 
upper wing. 

CAMBER The convexity or rise of the curve of an aero- 
foil from its chord, usually expressed as the ratio of 
the maximum departure of the curve from the chord 
as a fraction thereof. Top Camhrr refers to the top 
surface and Bottom Camber to the bottom surface of 
an aerofoil. Mean Cambrr is the mean of these two. 

CAPACITY-CARRYING The excess of the total lifting ca- 
pacity over the dead load of an aircraft. The latter 



318 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



includes structure, power plant and essential acces- 
sories. Gasoline and oil are not considered essential 
accessories. 

The cubic contents of a balloon. 
CAPACITY-LIFTING (See LOAD) The maximum flying 

load of an aircraft. 
CATHEDRAL A negative dihedral. 
CEILING The maximum possible altitude to which a 

given aeroplane can climb. 

CENTER The point in which a set of effects is assumed 
to be accumulated, producing the same effect as if 
all were centered at this point. 

There are five main centers in an aeroplane 
Center of Lift, Center of Gravity, Center of Thrust, 
Center of Drag and Center of Keelplane Area. The 
latter is also called the Directional Center. The sta- 
bility, controllability and general air worthiness of 
aeroplane depend largely on the proper positioning 
of these centers. 

CENTER OF PRESSURE OF AN AEROFOIL The point in the 
plane of the chords of an aerofoil, prolonged if neces- 
sary, through which at any given attitude the line 
of action of the resultant air force passes. (This 
definition may be extended to any body.) 
CENTER PANEL The central part of the upper wing (of 
a biplane) above the fuselage. The upper wings are 
attached to this on either side. 

CHORD (Of an aerofoil section.) A straight line tan- 
gent to the under curve of the aerofoil section, front 
and rear. 

CHORD LENGTH (Or length of Chord.) The length 
of an aerofoil section projected on the chord, extended 
if necessary. 

CLINOMETER (See INCLINOMETER.) _ 

CLOCHE The bell-shaped construction which forms the 

lower part of the pilot's control lever in the Bleriot 

control and to which the control cables are attached. 

COCKPIT The space in an aircraft body occupied by 

pilots or passengers. 
CONCENTRATION RING The hoop to which are attached 

the ropes suspending the basket (of a balloon). 
CONTROLS A general term applied to the mechanism 
used to control the speed, direction of flight and alti- 
tude of an aircraft. 

Bridge (Deperdussin-" Dep " Control) An inverted 
" U " frame pivoted near its lower points, by which 
the motion of the elevators is controlled. The ailer- 
ons are controlled by a wheel mounted on the upper 
center of this bridge. 
Dual Two sets of inter-connected controls allowing 

the machine to be operated by one or two pilots. 
Shoulder A yoke fitting around the shoulders of the 
pilot by means of which the ailerons are operated (by 
the natural side movement of the pilot's body) to 
cause the proper amount of banking when making a 
turn or to correct excessive bank. (Used on early 
Curtiss planes.) 

Stick (Joy-stick) A vertical lever pivoted near its 
lower end and used to operate the elevators and 
ailerons. 

COWLS The metal covering enclosing the engine section 
of the fuselage. 



CHOW'S FOOT A system of diverging short ropes for dis- 
tributing the pull of a single rope. (Used princi- 
pally on balloon nets.) 

DECALAGE The difference in the angular setting of the 
chord of the upper wing of a biplane with reference 
to the chord of the lower wing. 

DIHEDRAL (In an aeroplane) The angle included at the 
intersection of the imaginary surfaces containing the 
chords of the right and left wings (continued to the 
planes of symmetry if necessary). This angle is 
measured in a plane perpendicular to that intersec- 
tion. The measure of the dihedral is taken as 90 
deg. minus one-half of this angle as defined. 

The dihedral of the upper wing may and frequently 
does differ from that of the lower wing in a biplane. 
Lateral An aeroplane is said to have lateral dihedral 
when the wings slope downward from the tips to- 
ward the fuselage. 

Longitudinal The angular difference between the an- 
gle of incidence of the main planes and the angle 
of incidence of the horizontal stabilizer. 
DIRIGIBLE A form of balloon, the outer envelope of 
which is of elongated horizontal form, provided with 
a propelling system, car, rudders and stabilizing sur- 
faces. 

Non-Rigid A dirigible whose form is maintained by 
the pressure of the contained gas assisted by the car 
suspension system. 
Rigid A dirigible whose form is maintained by a rigid 

structure contained within the envelope. 
Semi-rigid A dirigible whose form is maintained by 

means of a rigid keel and by gas pressure.. 
DIVING RUDDER (See ELEVATOR.) 

DOPE A preparation, the base of which is cellulose 
acetate or cellulose nitrate, used for treating the 
cloth surfaces of aeroplane members or the fabric of 
balloon gas bags. It increases the strength of the 
fabric, produces tautness, and acts as a filler to make 
the fabric impervious to air and moisture. 
DRAG The component parallel to the relative wind of 
the total force on an aircraft due to the air through 
which it moves. 

That part of the drag due to the wings is called 
"Wing Resistance" (formerly called "Drift"); 
that due to the rest of the aeroplane is called " Para- 
site Resistance" (formerly called head resistance). 
The total resistance to motion through the air of 
an aircraft, that is, the sum of the drift and parasite 
resistance. Total Resistance. 

DRIFT The component of the resultant wind pressure 
on an aerofoil or wing surface parallel to the air 
stream attacking the surface. 

Also used as synonymous with lee-way. 
(See DRAG.) 

DRIFT INDICATOR An instrument for the measurement 
of the angular deviation of an aircraft from a set 
course, due to cross winds. 
Also called Drift Meter. 

DRIFT WIRES Wires which take the drift load and trans- 
fer it through various members to the body of the 
aeroplane. 
DRIP CLOTH A curtain around the equator of a balloon 



NOMI.M 1, ATI UK 1 (K A KK< >N A I TU s 



which prexents rain from dripping intu tin basket. 
DROOP 

(a) An aileron is said to h.-uc droop when ii ,. . 
justed tin! its trailing edge is In low tin- trilling edge 
of tin in nil plane. 

(6) When :i winy is warped In gixe wash out or wash ill, 
its trailing edge will. relatue to the le iding edge, be 
displaced progressively from on> . n.i to tin- otlu-r. 
A downward displaeeneBi is called droop. 

.IK.XXTOH A hinged surface, usually in tin- form of a 
hormuit.il niddi-r. inoiintcd nt the tail of an aircraft 
for controlling tin- longitudinal attitiulc of tin- air- 
craft, i. r.. it-, rotation about tin- lateral a\is. 
K \n-\\\ M.I A term applied to the tail group of parts 
in aeroplane. 

- Txn..) 

'.M.iNt SIM. BKARERS, STPPORTS The members form- 
mi: tin- engine lied. 

NHIIIM. F.IM.K The foremost part or forward edge of 
an arrofoil or propeller blade. 

ri The portion of the balloon or dirigible which 
contains the 
'.grxroR The largest horizontal circle of a spherical 

balloon 

'xiuiNi. A wood or metal form attached to the rear of 
struts, braces or wires to give them a streamline shape. 
;"'AIH LEAD A guide for a cable. 

FIN A small fixed aerofoil attached to part of an air- 
craft to promote stability; for example, tail fin, skid 
tin. ete. Fins may be either horizontal or vertical 
and are often adjustable. 

STXHII.IXER.) 
>'IKK D\MI A metal screen dividing the engine section 

of an aeroplane body from the cockpit section. 
jFi.n.iiT PATH The path of the center of gravity of an 

aircraft with reference to the earth. 

'i.o\ r That portion of the landing gear of an aircraft 
which provides buoyancy when it is resting on the 
surface of the water. 
i> Lvi\(. HOAT (See AEROPLANE.) 

'LXIM; POSITION The position of a machine, assumed 
when (lying horizontally in still air. When on the 
ground the machine is placed in a flying posi:ion by 
leveling both longitudinally and laterally. The two 
longerons, engine sills or other perpendicular parts 
designated by the maker are taken as reference points 
from which to level. 
OOT BAR (See RrnnER BAH.) 
i M;E (See BODY.) 

I.AI.K COVER A cover placed on a fuselage to pre- 
serve a streamline shape. 
JAP The shortest distance between the planes of the 

chords of the upper and lower wings of a biplane. 
>x- li xo (See ENVELOPE.) 

- To fly without power and under the influence of 
gravity alone. 

A form of aircraft similar to an aeroplane but 
without any power plant. 

When utilized in variable winds it makes use of 
the soaring principles of flight and is sometimes called 
a snaring machine. 

ANGLE (See ANGLE.) 



(MINK One ot tin- segments of fabric comprising t' 
I" of a balloon. 

( linn \n l to MI ( nix as placed mi the | pro 

i balloon. 

l(ri A long trailing rope alt irlicd to spherical 
balloon or dirigible to serve as a brake and as a vari- 
able ballast. 

GfY A rope, chain, wire ,.r rod attached to an objr.t 
t - . . "r sti iily it, such as guys to wing, tail or 
landing gear. 

1 1 xMiAB An aeroplane si 

HEAD KK-I.-TANCE (See PARASITE RKMSTANCB.) 

HELICOPTBR A form of aircraft whose support in the 
air i.s derived from the vertical thrust of prop- lit rs. 

HORN-CONTROL ARM An arm at right angles to a con- 
trol surface to which a control cable i, attach, d. for 
example, aileron horn, rudder horn, elevator horn, 
ete. Yore commonly called a Mail. 

Ill- 1. 1. t See Honv.) 

IN< : INOMKTEH An instrument for measuring the angle 

made by the axis of an aircraft with the horizontal. 
hiiliralor-Hankinff An inclinometer indicating lateral 
inclination or bank. 

INSPECTION WINDOW A small transparent window in 
the eim lope of a balloon or in the wing of an acr,. 
plane to allow inspection of the interior, or of aileron 
controls when the latter are mounted inside an aero 
foil section. 

INSTABILITY An inherent condition of a body, which, 
if tin- body is distributed, causes it to move toward 
a position away from its first position, instead of 
returning to a condition of equilibrium. 

KEEL PLANE AREA The total effective area of an air- 
craft which acts to prevent skidding or side slipping. 

KITE A form of aircraft without other propelling menus 
than the tow-line pull, whose support is derived from 
the force of the wind moving past its surfaces. 

LANDING GEAR The understructure of an aircraft de- 
signed to carry the load when resting on. or running 
on, the surface of the land or water. 

LEADING EDGE (See KNTKHISI; KIIOK.) 

LEEWAY The angle of deviation from a set course over 
the earth, due to cross currents of wind. Also called 
Drift. 

LIFT The component of the force due to the air pres- 
sure of an aerofoil resolved perpendicular to the 
flight path in a vertical plane. 

LIFT BRACING (See STAY.) 

LIFT-DRIFT RATIO The proportion of lift to drift is 
known as the lift-drift ratio. It expresses the effi- 
ciency of the aerofoil. 

LOAD 

Draii The structure, power plant and essential acces- 
sories of an aircraft. 

fill The maximum weight which an aircraft can 
support in flight; the gross weight. 

1'irful The excess of the full load over the dead 
weight of the aircraft itself, i. e., over the weight of 
its structure, power plant and essential accessories. 
(These last must be specified.) 

(See Capacity.) 
LOADING The weight carried by an aerofoil, usually 



320 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



expressed in pounds per square foot of superficial 
area. 

LOBES Bags at the stern of an elongated balloon de- 
signed to give it directional stability. 

LONGERON The principal fore-and-aft structural mem- 
bers of the fuselage or nacelle of an airplane. 
(See LONGITUDINAL.) 

LONGITUDINAL A fore-and-aft member of the framing 
of an aeroplane body, or of the float in a seaplane, 
usually continuous across a number of points of sup- 
port. 

LONGITUDINAL DIHEDRAL (See DIHEDRAL.) 

MAST (See HORN.) 

MONOCOQUE (See BODY.) 

MONOPLANE A form of aeroplane whose main support- 
ing surface is a single wing extending equally on 
each side of the body. 
(See AEROPLANE.) 

MOORING BAND The band of tape over the top of a 
balloon to which are attached the mooring ropes. 

NACELLE (See BODY.) 

NET A rigging made of ropes and twine on spherical 
balloons, which supports the entire load carried. 

NOSE DIVE A dangerously steep descent, head on. 

NOSE PLATE A plate at the nose or front end of the 
fuselage in which the longerons terminate. 

NOSE SPIN A nose dive in which the aeroplane rotates 
about its own axis due to the reaction from the pro- 
peller. It usually results from failure to shut off 
the engine in time when going into a nose dive, and 
is likely to cause complete loss of control. 

ORNITHOPTER A form of aircraft deriving its support 
and propelling force from flapping wings. 

OUT-RIGGER Members, independent of the body, ex- 
tending forward or to the rear and supporting con- 
trol or stabilizing surfaces: 

OVERHANG The distance the wings project out beyond 
the outer struts. 

PAN CAKE, To To descend as a parachute after a ma- 
chine has lost forward velocity. To strike the 
ground violently without much forward motion. 

PANEL A portion of a framed structure between adja- 
cent posts or struts. Applied to the fuselage it is 
the area bounded by two struts and the longerons. 
An entire wing is often spoken of as a panel. Thus 
the upper lifting surface of a biplane is usually of 
three parts designated as the right upper panel, left 
upper panel and the center panel. 

PARACHUTE An apparatus made like an umbrella used 
to retard the descent of a falling body. 

PARASITE RESISTANCE The total resistance to motion 
through the air of all parts of an aircraft not a part 
of the main lifting surface. 

PATCH SYSTEM A system of construction in which 
patches or adhesive flaps are used in place of the 
suspension band in a balloon. 

PERMEABILITY The measure of the loss of gas by diffu- 
sion through the intact balloon fabric. 

PHILLIPS ENTRY A reverse curve on the lower surface 
of an aerofoil, towards the entering edge, designed 
to more evenly divide the air. 

PITCH OF A PROPELLER (See PROPELLER.) 



PITCH OF A SCREW The distance a screw advances 
in its nut in one revolution. 

PITCH, To To plunge in a fore-and-aft direction. 

PITOT TUBE A tube with an end open square to the 
fluid stream, used as a detector of an impact pres- 
sure. It is usually associated with a concentric tube 
surrounding it, having perforations normal to the 
axis for indicating static pressure; or there is such 
a tube placed near it and parallel to it, witli a closed 
conical end and having perforations in its side. The 
velocity of the fluid can be determined from the 
difference between the impact pressure and the static 
pressure, as read by a suitable gauge. This instru- 
ment is often used to determine the velocity of an 
aircraft through the air. 

PLANE OF SYMMETRY A vertical plane through the 
longitudinal axis of an aeroplane. It divides the 
aeroplane into two symmetrical portions. 

PONTOON (See FLOAT.) 

PROPELLER OR AIR SCREW A body so shaped that its 
rotation about an axis produces a thrust in the di- 
rection of its axis. 

Disc-Area of Propellet The total area of a circle 

swept by the propeller tips. 
Pitch Of The distance a propeller will advance in 

one revolution, supposing the air to be solid. 
Race The stream of air driven aft by the propeller 
and with a velocity relative to the aeroplane greater 
than that of the surrounding body of still air. (Fre- 
quently called slip-stream.) 

Slip Of The difference between the distance a pro- 
peller actually advances and the distance it would 
advance while making the same number of revolu- 
tions in a solid medium. Usually expressed as a per- 
centage of the total distance. 

Torque Of The turning moment of the propeller. 
The effect of propeller torque is an equal reaction 
tending to rotate the whole aeroplane in the oppo- 
site direction to that of the propeller. 

PUSHER (See AEROPLANE.) 

PYLON A post, mast or pillar serving as a marker of 
a flying course. Also used infrequently to designate 
the control masts such as the aileron mast, rudder 
mast, elevator mast, etc. 

RAKE The angular deviation of the outer end of a wing 
from a line at right angles to the entering edge. 

RELATIVE WIND The motion of the air with reference 
to a moving body. Its direction and velocity, there- 
fore, are found by adding two vectors, one being the 
velocity of the air with reference to the earth, the 
other being equal and opposite to the velocity of the 
body with reference to the earth. 

RETREAT (See SWEEP BACK.) 

RIB A member used to give strength and shape to an 

aerofoil in a fore-and-aft direction. 
Web A light rib, the central part of which is cut out 

in order to lighten it. 

Compression A rib heavier than the web type and so 

constructed as to resist the compression due to the 

wire bracing of the aeroplane. 

Secondary Nose Small ribs extending from the front 

spar to the nose strip (entering edge). Placed be- 



No.MKNt LATt UK 1O|{ AERONAUTICS 



.!_ i 



tween tin- iii.iin rilis to give Mi|i|inrt to the fal.ru n, ..r 
tin- entering edge. Sometimes called Stuli Hibs. 

J(K,(.I.\(, Tin- art (if truing up .-in aeroplane ;ni<l ki . p 
ing it in Hying condition. 

Hii' ( mil) Tlic rope running from the rip pain 1 of a 
balloon to tin- basket, tin- pulling of which causes 
immediate deflation. 

HIP 1' \.\KI. A >trip in tin- upper part of a balloon 
which i* torn off" when immediate deflation is desired. 

Hi DIIKH A hinged or pivoted Mirf-ice, usually more or 
li -ss flat or streamlined, used for the purpose of eon 
trolling the attitude of an aircraft about its vertical 
axi.s, i. e., for controlling its lateral movement. 

KriMiKii BAH A bar pivoted at the center, to the ends 
of which the rudder control cables are attached. The 
pilot operates the rudder by moving the rudder bar 

With his feet. 

lit iiixii POST Tin- post to which the rudder is hinged, 

generalh forming the rear vertical member of the 

vertical staliili/er. 
Sr \ PLANE An aeroplane fitted with pontoons or floats 

suitable for alighting on or rising from the water. 

(See AEROPLANE.) 

SERPENT A short heavy guide rope used with balloons. 
SIHXINO A binding of wire, cord or other material. 

I'siially used in connection with joints in wood, and 

cable splices. 
SIHK Si. i PIMM. Sliding sideways and downward toward 

the center of a turn, due to an excessive amount of 

bank. It is the opposite of skidding. 
SIM U'ALK A reinforced portion of the wings near the 

fuselage serving as a support in climbing about the 

aeroplane. Otherwise known as running board. 
SKIDDING Sliding sideways away from the center of a 

turn, due to an insufficient amount of bank. It is 

the opposite of side slipping. 

SKIDS LANDING GEAR Long wooden or metal run- 
ners designed to prevent nosing of a land machine 

when landing, or to prevent dropping into holes or 

ditches in rough ground. Generally designed to 

function in case the wheels should collapse or fail to 

act. 
]- a i[ A skid supporting the tail of a fuselage while 

on the ground. 
H'ing A light skid placed under the lower wing to 

prevent possible damage on landing. 
SKIS FRICTION Friction between the air and a surface 

over which it is passing. 
SUP STREAM (See PROPELLER RACK.) 
SOMIIM; MAI IIINE (See GLIDER.) 
BPAN-WING Span is the dimension of a surface across 

the air stream. 
If ing Span or Spread of a machine is length overall 

from tip to tip of wings. 
SPARS-WING Long pieces of wood or other material 

forming the main supporting members of the wing, 

and to which the ribs are attached. 
SPHKAD (See SPAN.) 
STABILITY The quality of an aircraft in flight which 

causes it to return to a condition of equilibrium after 

meeting a disturbance. 
Directional That property of an aeroplane by virtue 



of which it ten. Is t.. hold a straight course. That is. 
if a machine ti mis constantly to xeer ori its course 
"< ..I the controls by the pilot 

to keep it on its course, it is said to lack directional 
stability . 

Dynamical The quality of an aircraft in flight which 
causes it to return to a condition of equilibrium after 
its attitude has been changed In mii.ui;> ...m. di> 
turbance, e. g., a gust. This return to equilibrium 
is due to two factors; first, the inherent righting mo- 
ments of the structure; second, the damping of the 
oscillations In the tail, i tc. 

Inherent Stability of an aircraft due to the disposi 
lion and arrangement of its fixed parts, i. e.. that 
property which causes it to return to its normal atti- 
tude of flight without the use of the controls. 
Lateral The property of an aeroplane by virtue of 
which the lateral axis tends to return to a horizontal 
position after meeting a disturbance. 
Longitudinal An aeroplane is longitudinally stable 
when it tends to fly on an even keel without pitch- 
ing or plunging. 

Statical In wind tunnel experiments it is found that 
there is a definite angle of attack such that for a 
greater angle or a less one the righting moments are 
in such a sense as to tend to make the attitude re- 
turn to this angle. This holds true for a certain 
range of angles on each side of this definite angle; 
and the machine is said to possess " statical stabil- 
ity " through this range. 

STABILIZER Balancing planes of an aircraft to promote 

stability. 

Horizontal A horizontal fixed plane in the empan- 

nage designed to give stability about the lateral axis. 

J'ertical A vertical fixed plane in the empannage to 

promote stability about the vertical axis. 
Mechanical Any mechanical device designed to se- 
cure stability in flight. 

STABILIZING FINS Vertical surfaces mounted longi- 
tudinally between planes, to increase the keel plane 
area. 

STAGGER The amount of advance of the entering edge 
of a superposed aerofoil of an aeroplane, over that of 
a lower, expressed as a percentage of the gap. It 
is considered positive when the upper aerofoil is for- 
ward. 

STALLING A term describing the condition of an aero- 
plane which, from any cause, has lost the relative 
speed necessary for steerageway and control. 

STATION The points at which struts join the longerons 
in a fuselage, are termed stations and are numbered 
according to some arbitrary system. Some makers 
begin with No. 1 at the nose plate aiiH number to- 
ward the rear. Other makers begin with at the 
tail post and number toward the front. 

STATOSCOPE An instrument to detect the existence of a 
small rate of ascent or descent, principally used in 
ballooning. 

STAY A wire, rope, or the like used as a tie piece to 
hold parts together, or to contribute stiffness; for 
example, the stays of the wing and body trussing. 

STREAMLINE-FLOW A term used to describe the cmidi 



322 



TEXTBOOK OF APPLIED AERONAUTIC ENGINEERING 



tion of continuous flow of a fluid, as distinguished 
from eddying flow, where discontinuity takes place. 

STREAMLINE-SHAPE A shape intended to avoid eddying 
or discontinuity and to preserve streamline-flow, thus 
keeping resistance to progress at a minimum. 

STRINGERS A term applied to the slender wooden mem- 
bers running laterally through the wing ribs for the 
purpose of stiffening them. 

STRUT A compression member of a truss frame; for in- 
stance, the vertical members of the wing truss of a 
biplane. 

STRUT-INTERPLANE A strut holding two aerofoils. 

SUPPORTING SURFACE Any surface of an aeroplane on 
which the air produces a lift reaction. 

SUSPENSION BAND The band around a balloon to which 
are attached the basket and the main bridle suspen- 
sions. 

SUSPENSION BAR The bar used for the concentration of 
basket suspension ropes in captive balloons. 

SWEEP-BACK The horizontal angle between the lateral 
(athwartship) axis of an aeroplane and the entering 
edge of the main planes. 

TACHOMETER An instrument for indicating the number 
of revolutions per minute of the engine or propeller. 

TAIL CUPS The steadying device attached at the rear 
of certain types of elongated captive balloons. 

TAIL-NEUTRAL A tail, the horizontal stabilizer of which 
is so set that it gives neither an upward lift nor a 
downward thrust when the machine is in normal 
flight. 

Positive A tail in which the horizontal stabilizer is so 
set as to give an upward lift and thus assist in carry- 
ing the weight of the aeroplane when it is in normal 
flight. 

Negative One in which the horizontal stabilizer is so 
set as to give a downward thrust on the tail when the 
machine is in normal flight. 

TAIL POST The vertical strut at the rear end of the 
fuselage. 

TAIL SKID A skid supporting the tail of a fuselage while 
on the ground. 

TAIL SLIDE A steep descent, tail downward. Usually 
caused by stalling on an attempt to climb too steeply. 

THIMBLE An elongated metal eye spliced in the end of 
a rope or cable. 

TRACTOR (See AEROPLANE.) 

TRAILING EDGE The rearmost portion of an aerofoil. 

TRIPLANE A form of aeroplane whose main supporting 
surface is divided into three parts, superimposed. 

TRUSS The framing by which the wing loads are trans- 
mitted to the body ; comprises struts, stays and spars. 

UNDERCARRIAGE (See LANDING GEAR.) 

VETTING The process of sighting by eye along edges 
of spars, planes, etc., to ascertain their alignment. 
An experienced man can detect and remedy many 
faults in alignment by this method. 

VOL-PIQUE' (See NOSE DIVE.) 
VOLPLANE To glide. 

WARP To change the form of the wing by twisting it, 
usually by changing the inclination of the rear spar 
relative to the front spar. 



WASHIN A progressive increase in the angle of inci- 
dence from the fuselage toward the wing tip. 

WASHOUT A progressive decrease in the angle of inci- 
dence from the fuselage toward the wing tip. 

WEIGHT-GROSS (See LOAD, FULL.) 

WINGS The main supporting surfaces of an aeroplane. 
Also called Aerofoils. 

WING FLAPS (See AILERON.) 

WING LOADING (See LOADING.) 

WING MAST The mast structure projecting above the 
wing, to which the top load wires are attached. 

WING RIB A fore-and-aft member of the wing structure 
used to support the covering and to give the wing 
section its form. (See RIB.) 

WING SPAR OR WING BEAM A transverse member of the 
wing structure. (See SPARS-WING.) 

WIRES 

Drift Wires that take the drift load and transfer it 
through various members to the body of the aero- 
plane. 

Flying The wires that transfer to the fuselage, the 
forces due to the lift on the wings when an aeroplane 
is in flight. They prevent the wings from collapsing 
upwards during flight. 

Landing The wires that transfer to the fuselage, the 
forces due to the weight of the wings when an aero- 
plane is landing or resting on the ground. 
Staggei The cross brace wires between the inter- 
plane struts in a fore-and-aft direction. 

YAW To yaw is to swing off the course and turn about 
the vertical axis owing to side gusts of wind or lack 
of directional stability. 

Angle Of The temporary angular deviation of the 
fore-and-aft axis from the course. 

ACCELERATION The rate of increase of velocity. 

CENTER OP GRAVITY The center of gravity of a body 
is that point about which, if suspended, all the parts 
will be in equilibrium, that is, there will be no tend- 
ency to rotation. 

CENTRIFUGAL FORCE That force which urges a body, 
moving in a curved path, outward from the center of 
rotation. 

COMPONENT A force which when combined with one or 
more like forces produces the effect of a single force. 
The single force is regarded as the resultant of the 
component forces. 

DENSITY Mass per unit of volume; for instance, pounds 
per cubic foot. 

EFFICIENCY (Of a machine.) The ratio of output to 
input of power, usually expressed as percentage. 

ELASTIC LIMIT The greatest stress per unit area which 
will not produce a permanent deformation of the ma- 
terial under stress. 

ELONGATION When any material fails by tension it 
usually stretches and takes a permanent set before it 
breaks. The ratio of this permanent elongation to 
the original length, expressed as a percentage, is a 
measure of the elongation. 

ENERGY The capacity of a body for doing work. Hc.it 
is a form of energy. Any chemical reaction that gen- 
erates heat or electricity liberates energy. Bodies 



NOMENCLATURE 1O1{ .\KMo.\.\l IKS 



in i;. piissi ,s i 111 rax |i\ virtue of liixinu work done 
ii|inii tin in 

I viiiiiiiiMM \\lnn tun or more turns u-t upon a 

hodx in such .1 wax that im iiuitiuii results, then i> 
saiil I" IM- equilibrium. 

I I xi i"ii "i >\ihix Tin ral in of tin- load required to 

: nliiri- in n slnu-tur.-il member to tin- usual 
uorkmg load tin- member is designed In carrx. Thus 
if a ini-iiilii-r hr designed to carry a loud t ..mi Ihs. 
nnd it would require a load of -JIMIII His. to cause fail- 
ure, the factor of .safety would lie four. 
I -"I I'. MM) The foot pound is n unit of work. It is 
equal to a force of one pound acting through a dis 
taiicc of one foot. This is a font pound nl energy. 

ISHITM That property of a body by virtue of which 
it resists any attempt to -start it if at rest, to stop 
it if in motion, or in any wax to cli.mge either the 
direction or xilocity of motion, is called Inrrlia. 

M x-s The mass of a body is a measure of the quantity 
of material in it. 

MMXHNI Moment is the product of n force times its 
lexer arm. It is usually expressed in Inch-I'oundi. 

\lo\u NII \i Momentum is the product of the mass and 
velocity of a moving body. It is a measure of the 
quantity of motion. 

POWER Power is the time rate of doing work. 

llnrir power The horsepower is a unit of work. One 
horsepower represents the performance of work at 
the rate of 33,000 foot-pound* per minute, or 550 
foot pounds per second. 

RESTLTANT OF A FORTE The resultant of two or more 
forces is that single force which will produce the 
same effect upon a body as is produced In the joint 
action of the component forces. 

STRK*S The internal condition of a body under the ac- 
tion of opposing forces. The unit of measure is 
usually pounds per square inch. 

Comprrttion When forces are applied to a body in 
such n war as to tend to crush it, there results a com - 
prcssive stress in the body. 
Trntion When forces are applied to a body in such 



a way as to tend to separate or pull it apart, the 

Iwidx is said t.i I tension or a tensile stress has 

1 i n produced within it. 

Shrur When external forces are applied in such a 
wax is ti> cause a tendency for particles of a body 
to slip or slide past each other, there results a sin ir 
mg stress in the hodx. 
> in \ix Strain is the deformation produced in a body 

by the application of external f"! 

ToHvi'K U In n forces are so disposed as to cause or 
tend to cause rotation, then- is produced a turning 

in nl which is also called tori|iie. It is usually 

measured in inch pounds. Thus if a force of 10 
pounds be applied tangcntially to the rim of a wheel 
of lO-inch radius, the torque or turning moment will 
be KM) inch pounds. 

L'LTIMATE STRENGTH The load per square inch re- 
quircd to produce fracture. 

VELOCITY In uniform motion, the distance passed over 
in n unit of time, as one second. This may also be 
obtaitied hy dividing the length of any portion of 
the path hy the time taken to describe that portion, 
no matter how small or great. 

In variable motion, where velocity varies from (Miint 
to point, its value at any point is expressed as tin- 
quotient of an infinitely small distance, containing 
tin- given point hy the infinitely small portion of 
time in which this distance is described. 

WORK The product of a force by the distance described 
in the direction of the force by the point of applica- 
tion. If the force moves forward it is called a work- 
ing force, and is said to do the work expressed hy 
this product; if backward, it is called a resistance, 
and is then said to have the work done upon it, in 
overcoming the resistance through the distance men- 
tioned (it might also be said to have done negative 
work). 

In a uniform translation, the working forces do an 
amount of work which is entirely applied to overcom- 
ing the resistance*. 



The Metric System 



The Metric System 

The fundamental unit of the metric system is the METER (the unit 
of length) From this the units of mass (GRAM) and capacity 
(LITER) are derived. All other units are the decimal subdivisions or 
multiples of these. These three units are simply related, so that tc 
all practical purposes the volume of one kilogram of water (one liter) 
iv , (jiial to mi'- cubic decimeter. 



One short ton equals ahout .91 metric ton; one long ton equals abou 
1.02 metric tons, and one kg. equals about 2.20 pounds. 



EQUIVALENTS 
1 METER = 39.37 INCHES 



PREFIXES MEANING UNITS 


Legal Equivalent Adopted 


by Act of 


Congress, July 28, 1866. 


MILLI- =; one thousandth Viooo -001 
CENTI- = one hundredth Moo .01 METER for length 






Length 




DEC1 one tenth Via -1 
unit : me 1- GRAM for mass 


Centimeter 
Meter 


r 


0.3937 

3.28 


inch 

feet 


IllcTO- = on" hundred lK 100. LITER for capacity 


Meter 
Kilometer 


= 


1.094 
0.621 


yards 
statute mile 


KILO- one thousand i 1000. 


Kilometer 


= 


0.5396 


nautical mile 


The metric terms are formed by combining the words "METER, 


Inch 
Foot 


_ 


2.540 
0.305 


centinit ters 
meter 


"GRAM," and "LITER" with the six numerical prefixes. 


Yard 





0.914 


meter 


Length 


Statute mile 





1.61 


kilometers 


10 milli-meters mm = 1 centimeter cm 


Nautical mile 


= 


1.853 


kilometers 


10 centi-meters 1 deci-meter dm 






. 




10 deci-meters = 1 METER (about 40 inches) m 






Area 




10 meters = 1 deka-meter dkm 


Sq. centimeter 





0.155 


sq. inch 


10 deka-meters = 1 hectometer 


Sq. meter 





10.76 


sq. fiet 


10 hecto-meters 1 kilo-meter (about % mile) km 


Sq. meter 





1.196 


sq. yards 


Mass 


Hectare 


=: 


2.47 


acres 


10 milligrams mg =1 centi-gram eg 
10 centi-grams = 1 deci-gram dg 
10 deci-grams 1 GRAM (ahout 15 grains) g 
10 grains = 1 deka-gram dkg 
10 deka grams = 1 hecto gram hg 
10 hecto-grams = 1 kilogram (about 2 pounds) kg 


Sq. kilometer 
Sq. inch 
Sq. foot 
Sq. yard 
Acre 
Sq. mile 


= 


0.386 
6.45 
0.0929 
0.836 
0.405 
2.59 


sq. mile 

sq. centimeters 
sq. meter 
sq. meters 
hectare 
sq. kilometers 


Capacity 






Volume 




10 nulli-liters ml =1 ccnti-liter cl 


Cu. centimeter 


= 


0.0610 


cu. inch 


10 centi-liters = 1 deci-liter dl 


Cu. meter 





35.3 


cu. feet 


10 deci-liters = I LITER (ahout 1 quart) 


Cu. meter 





1.308 


cu. yards 


10 liters = 1 deka-liter dkl 


Cu. inch 





16.39 


cu. centimeters 


10 deka-liters = 1 hecto-liter (ahout a barrel) hi 


Cu. foot 





0.0283 


cu. meter 


10 hecto-liters = 1 kilo-liter kl 


Cu. yard 


= 


0.765 


cu. meter 


The square and cubic units are the squares and cubes of the 






Capacity 




linear units. 










The ordinary unit of land area is the HECTARE (ahout 2% acres). 


Milliliter 





0.0338 


U. S. liq. ounce 


Length 


Milliliter 
Liter 


_ 


0.2705 
1.057 


apoth. drain 
U. S. liq. quarts 


1.000 millimeters (mm) or 100 centimeters (cm) = 1 meter (m). 
1.000 m = 1 kilometer (km). 


Liter 
Liter 
Dekaliter 


z! 


0.2642 
0.908 
1.135 


U. S. liq. gallon 
U. S. drv quart 
U. S. pecks 


Capacity 


Hectoliter 





2.838 


U. S. bushels 


1,000 milliliters (mil) or cubic centimeters (cc) 1 liter (1). 
1,000 1 = 1 kilometer (kl) or cubic meter (cm m). 


U. S. liq. ounce 
U. S. apoth. dram 
U. S. liq. quart 


zT 


29.57 
3.70 
0.946 


milliliters 
milliliters 
liter 


Weight 


U. S. dry quart 


= 


1.101 


liters 




U. S. liq. gallon 





3.785 


liters 


1,000 milligrams (mg) = 1 gram (g). 


U. S. peck 


- 


0.881 


dekaliter 


1.000 g= 1 kilogram (kg). 1.000 kg = 1 metric ton. 


U. S. bushel 





0.3524 


hectoliter 


A dollar is divided into 100 cents or 1,000 mills, just as the meter 










is divided into 100 centimeters or 1,000 millimeters. And as, for 






Weight 




example, 2 dollars and 25 cents is written $2.25, so 2 meters and 25 










rrntimeters is conveniently written 2.25m. Meters, liters and grams 
are treated in the same way as dollars. For practical purposes, from 


Gram 
Gram 


= 


15.43 

0.772 


grains 
U. S. apoth. scruple 


units of length are formed the squares, cubic or capacity measures (a 
cubic measure 10 cm. on each edge, or 1,000 cc., makes 1 liter) and 


Gram 
Gram 


ii 


0.2572 
0.0353 


U. S. apoth. dram 
avoir, ounce 


the weights (1 cc. of water weighs 1 gram). 


Gram 
Kilogram 


= 


0.03215 
2.205 


troy ounce 
avoir, pounds 


Length 


Kilogram 


zr 


2.679 


troy pounds 


For all practical purposes 3 feet and 3% inches equal 1 meter or 
100 centimeters, and 1 inch equals 2.5 cm. The exact legal equiva- 
lent for the United States is 39.37 inches to 1m. 


Metric ton 
Metric ton 
Grain 
U. S. apoth. scruple 


= 


0.984 
1.102 
0.0648 
1.296 


gross or long ton 
short or net tons 
grams 
grams 


Capacity 


U. S. apoth. dram 





3.89 


grams 


One liter equals 1.0567104 liquid quarts or ahout .91 dry quart. 


Avoir, ounce 





28.35 


grams 


One fluid ounce equals about 29.57 milliliters or cc. 


Troy ounce 





31.10 


Jrams 


Weight 


Avoir, pound 





0.4536 


ilogram 




Troy pound 





0.373 


kilogram 


In avoirdupois weight one ounce equals nearly 28.25 grams; one 


Gross or long ton 





1.016 


metric tons 


pound, exactly 453.5924277 g. nearly 454 g. or 454 kg. 


Short or net ton 




0.907 


metric ton 





LENGTHS 



INCHES 




MILLI- 
METERS 


INCHES 


CENTI- 
METERS 


FEET 


METERS 


U. S. Yards 




METERS 


U..S. Miles 


KILO- 
METERS 


0.03937 




1 


0.3037 


1 


1 


= 0.304801 


1 


- 


0.914402 


0.62137 = 


1 




0.07874 




2 


0.7874 


= 2 


2 


= 0.609601 


1 093611 




1 


1 


1.60935 


0.11811 




3 


1 


J..")4001 


3 


- 0.914402 


2 





1.828804 


1.24274 = 


2 


0.15748 




4 


1.1811 


= 3 


3.28083 


= 1 


2.187222 





2 


1.86411 = 


3 


0.19685 





6 


1.5748 


= 4 


4 


= 1 219202 


3 




2.743205 


2 


3.21869 


0.23622 




6 


1.9685 


= 5 


5 


= 1.524003 


3.280833 




3 


2.48548 = 


4 


0.27559 




7 


2 


= 5.08001 


6 


= 1.828804 


4 




3 657607 


3 = 


4.82804 


0.31496 




8 


2.3622 


= 6 


6.56167 


= 2 


4.374444 





4 


3.10685 = 


5 


0.35433 




9 


2.7559 


= 7 


7 


= 2.133604 


5 





4.572009 


3.72822 = 


6 


1 




25,4001 


3 


7.62002 


8 


= 2.438405 


5.468056 




5 


4 


6.43739 


2 




50.8001 






9 


=: 2.743205 


6 





5 486411 


4.34959 = 


7 


3 




76.2002 


3.5433 


= 9 


9.84250 


= 3 


6.561667 


- - 


6 


4.97096 = 


8 


4 




101.6002 


4 


= 10.16002 


13.12333 


= 4 


7 





6 400813 


5 


8.04674 


6 




127.0003 


5 


= 12.70003 


16.40417 


= 6 


7.655278 


_ 


7 


5.59233 = 


9 


6 




152.4003 


6 


== 15.24003 


19.68500 


= 6 


8 





7 315215 


6 


9.65608 


7 




177.8004 


7 


17.78004 


22.96583 




8.748889 


. 


8 


7 


11.26541! 


8 




203.2004 


8 


20.32004 


26.24667 


g 


9 


_ 


8 229616 


8 


12.8747H 


9 




22S.6005 9 


- 22.86005 29 52750 


= 9 9.842500 


-- 


9 


9 


14.48412 



324 



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JAN 25 1934 



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YE 018' 







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UNIVERSITY OF CALIFORNIA UBRARY